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Showing posts with label process. Show all posts
Showing posts with label process. Show all posts

Friday, 17 February 2017

Double grade printing.


From time to time I find it strange the way events come together! for instance, I was in the darkroom working on some prints that I could not get the sky to burn in properly. There was nothing unusual in me burning in the sky, most of the photographs I produce have had the skies enhanced in some way. But this time I could not get it the way I wanted it.


The strangeness in this case was that a few days before, I was reading a thread on my favourite forum about how to deal with whited out skies when printing. I took part giving an account of my method of dealing with it. One of the other contributors suggested split grade printing. But when he described the process it is more akin to double grade printing - this is where you use another grade to bring out part of the image that will not burn in at the grade you are using.


All the circled images needed double grade printing.

The process:


The contact print in this case suggested that the stone work of the building and sky were under exposed when compared to the reflection. The segmented test print (grade 2) proved this by indicating that it may need to be burned in for an extra twenty seconds above base exposure of thirty seven seconds. Even with the extra light it did not make the difference. After a further print and forty seconds burn in, it still was not right. I decided to see if changing to a harder grade when burning in would make the difference.

With the discussion still fresh in my mind I opted to use the double grade method to see if it would solve the problem I was having. I normally would have used pre flashed paper but that would mean starting all over again with a pre-flashed test strip. I chose the simpler route of dialing in a harder grade, in this case 4, before burning in the sky and face of the building.

The red area indicates the over lap area of the mask.
Something to consider:

When using this method certain negatives can produce a grainier look to the picture which may not be to your liking and you need to be careful not to knock the masking frame when changing the settings and using the mask.

The burning in method:

It takes practice to get this method to look natural, which is easy to master when you have a nice defined area without things like buildings poking up above the horizon. A piece of card is needed to use as a mask. You do not need to use black card but if you have some all well and good. Otherwise any card will do, if one side is brighter than the other you should always make that side face the lens to reflect the light back. In my opinion you should make the mask smaller than the site that needs covering. Because the card is kept moving it will make up for the under size when used with an up and down motion. If you don't you can end up with a lighter shaded area a bit like an out line you would get if it was still. When you get it right it is very satisfying.

 Result:

I used forty seconds at grade four to burn in the building and sky. How did I know it would work? I further considered the segmented test print, took a calculated risk and listened to the little voice in the back of my head. In other words I went with the creative flow.

 

Basic outline for split grade printing.

Saturday, 16 May 2015

Contaminated by wetting agent?

Developed in RO9 but it is not the developer.
When something unexpected happens while you are processing your negatives, it takes a bit of time to get your head round it. This happened while I was processing a number of rolls of film in R09 and using it's special brother.

 The problem has shown it's self by producing very blotchy negatives affecting two rolls of the six film developed. When this happens in a run of developing it is difficult to work out what circumstances are different enough to point a finger at.

Please bear in mind that the elimination process was written after I discovered the culprit.

Fomapan 100 negatives developed in RO9
Process of elimination:

  1. So where to start? It is fortunate that the negatives involved were not the ones processed in the RO9 special. The RO9 developed one's were. This made the investigation more straight forward in that I have a better understanding of how RO9 works.
  2. Was it the developer? It was made up seconds before it was used in the usual way.
  3. What about Stop and Fix? Both were freshly made up minuets before use. So it cannot be one of the three main players? As they are all fresh.
  4. OK what about the method? No difference there either I used my usual inversion sequence.
  5. Processing tanks? Well I did press a tank into use that I have not used in a long time because of the quantity of film that needed to be developed.
  6. Could that be the answer?
  7. Did it affect one make of film in particular? No it did not, again this could have been a fortunate coincidence in that a roll of FP4+ and Fomapan 100 show the same affect. If it had only happened to one make it could have been construed as a manufacturing fault.
  8. Water? It was fresh and clean and there had not been any notices to say there was a problem with the drinking water.
  9. That leaves wetting agent? Hold on now that points to something I noticed when I was using PMK Pyro some years ago, I had a roll of film with the same sort of pattern. I put it down to the developer which I have
    Film FP4+ developed in PMK Pyro
    not used since. Thinking back to that time I had noticed that every time I opened the dev tank to pour out the developer there were a lot of bubbles in the top. That looked soapy and diminished with each step of the process which would suggest developer. I did speak to a number of other photographers at the time who suggested it was a developer fault. Although I stopped using the developer substituting it for ID11 and the problem disappeared was not convinced at the time. I changed how the kit was washed after each processing session. After a while I also stopped adding wetting agent to the tank. Using a different tank with it already added. Dunking the reel in by it's self and then soaking the reel in a bucket of water with a good resin afterwards.
Looking back I think when I pressed the other developing tank into use I mistakenly picked up the one I had been using for wetting agent. The resulting blotchy pattern is the result of its contamination.

This print was made from the same contaminated
Negatives. note no blotchy marks.

Conclusion:

Having eliminated all the other possibilities and no matter how silly it may sound the wetting agent is the culprit in this case. It has this time affected nearly all the frames on each film, when it happened some years ago (after checking the negatives) only certain frames showed signs of being blotchy. Which would indicate a weak contamination of the film process. This is only the second time I have had this problem in all the years I have been developing film. It just goes to show that something as innocuous as soap can cause so much trouble if it is not washed away conclusively after every processing session when added to the developing tank. My suggestion is to put wetting agent in a separate container and add the reel and film to it and not the other way round.

This picture shows that the blotches are prominent
In the sky but not the foreground.

When printing the affected negatives you cannot see the blotches when looking down the focus finder. Even though the contact prints show it quite clearly.

All the photographs that appear with this article were printed from the dodgy neg's. As I mentioned not all suffered the soapy demise. 


Monday, 10 February 2014

Easy Lith 200 Results.

This is my follow on post explaining what happened and how it was done. Not everything went according to plan, but more about that later.

Being in a fortunate position of owning a second slot processor I decided to set this at 26 degrees for the lith developer. I did not add stop or fix to the other slots but continued to use what was already available in the other slotty, keeping the temperature to 20 degrees. It is just as well I did as one of the papers emulsion became very soft.

I chose high contrast negatives that I had already printed. I looked back through my notes on how long each was exposed for and added one and half times more exposure to see how things worked. I chose to follow the instructions when it came to diluting part A and B at 2X 1+25+1000 mls water. (20 mls of each 40 mls in total in 1000 mls of water). The paper I chose to start with was Kentmere RC because it was the paper originally used with these negatives. All the prints were exposed to white light, no grades were set. I had no idea how they would turn out or what sort of tone would be produced. I used two other varitone RC papers to see which produced the best results with this mix of A and B.

Kentmere paper
This is the original Kentmere print exposed at grade zero and developed as normal.

Kentmere paper
This is the first print out of the easy lith on Kentmere paper. It took over three minutes for it to reach full development. A very faint out line of the picture started to show about 30-40 seconds in. It was difficult to see whether the print had toned or not with the red light on.

Foma 131 paper
Second print was on Foma 131 varitone. This took a full twelve minutes to develop fully and is what I had in mind as a lith look.

Ilford paper
Third print was on Ilford multigrade paper, I pulled the paper early because I thought it may go completely black.

Conclusions:

Not knowing what to expect from this process makes it difficult to be to critical with the results. One of my main mistakes was to treat this like a normal developer, I should have mixed the two parts separately so I could vary the strengths of each part to get a look that was in my opinion more lith like, this may have lead me to make changes to the amount of over exposure as well. The problem I think in these early stages of getting to grips with a new process such as this is there are a lot of variables to take into account. With more practice I suspect I will arrive at something more my taste.

A side affect of using the Lith process has shown up a weakness in what I considered a well vented darkroom. This is the first time I experienced a build up of fumes. Some updating needs to be carried out if I wish to continue printing using lith chemicals. After a bit of thought I feel it should be upgraded regardless!

Over all I am pleased with the outcome, for a first attempt. Others may not, but I would prefer to get as many of the mistakes out of the way now so I can concentrate on producing finer prints in the future.

Link back to first post easy lith 200

Thursday, 8 November 2012

Out of date HP5+ develpoed in ID11


Lomo Fisheye two
Now that my brain is back in gear I can get on with developing that errant 35mm HP5+. Hopefully it should go without a hitch.



As far as I can remember (going by recent events that’s a bit dubious) this film is about seven years out of date. With this in mind you would of thought I should have picked a camera that allowed ISO adjustments. I didn't! Lomo's fisheye 2 was the camera chosen meaning that the HP5+ would have to be exposed at box speed (400 iso) Unlike a lot of people I don't have a problem with box speed and anyway it is in the best tradition of the toy camera cult along with Light leaking cameras, plastic lens, unpredictable focus and a lot of fun.


When it comes to box speed Ilford suggest that HP5+ should be developed for thirteen minutes at 20 degrees C. in ID11. From what I can remember of this all round developer it should produce negatives that are not very grainy. Normally I would have developed the film at the indicated time and be dammed. But something at the back of my mind said that fifteen minutes would do a better job and I prefer the negatives to be a bit on the dense side which translates to clear defined rectangles of tone. This must not be over done though as increasing the printing times could lead to over heating the negative making it buckle in the negative carrier of the enlarger. Leading to out of focus or soft pictures.


After all these years I still get the little bit of apprehension as I do a quick check of the film just before the wash stage. I need not have worried as I remove the reel from the developing tank I can just make out a line of rectangles along the film. The proof of the pudding will be when I print them.





 

I am very pleased with the way these negatives have printed. There is no sign of grain even though they have been enlarged to fit 9.5”x12” paper. I have used Silverproof matt paper at grade three and processed in Moersch 6 blue tone developer. Which produces a rich blue black that does not translate very well from scanned pictures.

Monday, 15 October 2012

An insight into making up ID11


Ilfords ID11
Ilfords ID 11 is the starting point for many a photographer wishing to develop there own monochrome negatives. It is one of the most popular pre-packaged powdered developers on the market along with Kodak's D76. The attributes of these developers are almost identical. Some photographers are put off initially from using these developers because it is in powdered form, but you needn’t be, they are straight forward to make up.


I have used both these developers before and for a long time almost exclusively when it came to processing my film. I recently exposed an out of date roll of 35mm HP5 film. I decided to make up a new batch of ID 11. I know how good or bad these negatives will be without having to do a test.


The kit: (to make up five litres)

    The mixing kit.
  • Measuring jug, that will take at least Four litres of fluid.
  • Thermometer.
  • Mixing stick
  • Five litre storage container
  • Bucket if you do not have large enough measuring jug for mixing.
  • Disposable gloves, Face masks if you think it is necessary.
  • Ilfords ID 11, in this case.

If you are new to making up ID 11 take your time.


Remove the two packets from the box and then tear or cut the box open. On the inside are the instructions for making the powder into a fluid. What follows is how I made up the developer from those instructions.



Adding packet A of the waterr
The box of powder I have purchased will make up five litres of stock solution enough to process fifty roll 35mm or 120 film (medium format). Once I have all the equipment in place, I warm the measuring jug and bucket with boiling water to stop the water loosing heat to the containers by conduction. Then bring the water to a temperature of 40 degrees centigrade (104 degrees F) making up 3.75 litres. Which I transfer to the bucket ( do not forget to remove the boiling water first) for mixing, checking to make sure that there has been no heat loss with the thermometer. I use this method because my measuring jug will only make up 2 litres at a time. Once the water is ready open packet marked A and pour in the powder slowly, while you stir, making sure that the powder does not clump together. Keep string until it is all dissolved (Always pour the powder into the water and not the other way round and add the powders in the right order) it will not take very long to add the contents of packet A. Now open the packet marked B and again add to the solution slowly stirring all the time this will take longer to add as it is a far larger amount of powder (make sure you do your mixing in a well ventilated room). Keep stirring after all the powder has been added to make sure it has all dissolved. Now stir in another 1.25 litres of water at room temperature making it up to the full 5 litres. With the help of a funnel I pour the developer into its storage container and allow it to cool.

Adding packet B of the developer


I usually make up my ID11 the day before. It will take an hour to cool ten degrees depending on what material your storage container is made of.








Pouring developer into storage container after the
Final  2Litres of water have been added.
I use this developer at 1+1 in most cases and as a single shot (use once and throw away) but it can be reused as long as you adjust the time to allow for it:

  • Two film add ten percent.
  • Three film add twenty percent.
  • Four film add Thirty percent.
  • Five film add forty percent.
  • Ten film add Ninety percent do not re-use above this amount.


Developer in storage container
coolling down before cap is
secured.
ID11 can be used with the following film from the Ilford range and many other makes besides: HP5+,Fp4+, Pan F+, Delta 100 Pro Delta 400 Pro, Delta 3200 Pro, SFX 200. It can also be used at three different dilutions: stock, 1+1 and 1+3. So the times for HP5+ exposed at 400 ISO, developed at twenty degrees C would be 7.30 minutes at stock, 13 minutes at 1+1 and 20 minutes at 1+3.

For more film makes, developer combination and times visit digital truthsmassive Dev chart.

  
How did the roll of HP5+ turn out? You will have to wait and see.

Sunday, 30 September 2012

Alternative way to check your fix is still fresh.


Here are two simple and easy ways of checking that the fix is not exhausted. The bottom line is if in doubt, throw it out.

  1. Take a drop of fix and place it on some blue litmus paper, if it turns red the fix is still active, if the paper remains blue it is exhausted. Rapid acting fixes by their nature will get exhausted more quickly than an ordinary one. When fixing paper you may expect to get thirty to forty 18 x 24 cm ( 8”x 10”) sheets per litre.
  2. Take ten ml of fix and add ten drops of potassium iodide solution to the measuring jar and stir. If the milky solution does not clear after it has been shaken then the fix is exhausted and a new batch should be made up. If it clears the fix is OK to use. Make up your Potassium iodide solution from two point five grams of powder and add a thousand ml of water and mix. This method does not apply to rapid fixes.

These methods will work for your film fixes as well. But the milk test you do for film will not work with paper as you cannot see this stage with paper.

Saturday, 11 August 2012

Stop not buffer.



One of the most popular over the counter acid stops.
Made from citric acid with colour indicator.
Stop is the second part of the development process, but how many of us give it a second thought. Most of us when we come to developing our first film tend to do what the manufacturers, friends and teachers suggest without delving into what the relationship is between these elements in the process. There is nothing wrong with this approach we are all eager to get on and see those all important first images. With success, we continue settling in to a way of doing things that produce good results. It's not until we start printing that some faults with the negatives rear their heads. Dust and hair marks being the most common but then there are those odd black spots appearing in the skies here and there. This is when the controversy about how we stop the development process comes to the fore.


There are two main categories. The more aggressive with chemicals and the gentler water stop. The later is not a stop and it is misleading to call it such.   It dilutes the developer to the point where it no longer has an affect on the emulsion this can and does lead to unevenly developed negatives and I cannot understand why it is recommended (for film only) other than to increase the longevity of the fix, a buffer or as a way of creating a certain style to the negative. 

Have been processed using a citric acid stop.
I personally prefer the more aggressive chemical route, when the stop go's in, the developer is stopped in its tracks producing a clean crisp negative but you need to be careful.

A popular choice in the make up of developers is Sodium carbonate, an alkali. When this comes into contact with an acid based stop it produces carbon dioxide gas that leads to blistering of the more sensitive film emulsion,( not the case with enlarging papers). It manifests its self as a pinhole in the denser areas of the negative. There are ways around this by using developers that are formulated from mild alkalis either balanced or borax which do not produce the damaging over heating or gas when used with acid stops.


A reflection of St Pauls in London.
Processed and printed using all Ilford products
Stops are made from several different acids the most popular is acetic with a pH dye indicator. The others are citric and boric. You can also use a simple solution of sodium bisulfite. Be careful which stop you choose as some produce green staining with some enlarging papers. Another precaution is to use the stop bath at a lower working temperature to the developer; I know this is a controversial move but I have used this method for years without any of the problems suggested by others.

Monday, 4 June 2012

Adox art series to be developed in PMK pyro.


Adox art series CHS 100. ISO 100


It has been a long time since I mentioned that I was going to do a test development using PMK Pyro on Adox  CHS 100 art series. What with the weather being unseasonally wet and other things getting in the way I have not been able to do the test exposures. I prefer to take the pictures outside on a bright day without fast moving clouds. Something that has not been forthcoming. The light level needs to be constant for the eighteen frames it takes to produce three test strips of two F numbers over and two F numbers under the metered reading. 



I'm pleased to say that the other day, weather and time to expose the film coincided which has resulted in a film waiting to be developed. Something that requires a spare four hours to do whether all in one go or over several days. See Agfa test formethod.

Monday, 2 April 2012

Processed print faults



Exhausted Developer
With all the processes that need to go well when producing a print in the darkroom it is surprising that faults are not more common. Even so the odd  one comes along to de-rail a good printing session. It does not matter how experienced you are sods law trips us all up!


Exhausred stop


Here are some of the most common faults: 



         Chemical fingers - this where odd irregular marks appear on the finished print usually at the edges. Make sure your hands are free from chemical contamination and dry before you handle photographic paper.

         Exhausted developer - fails to produced a full image once it has reached its completion time.
Exhausted Fix

         Wrongly diluted developer - produces faint grainy image. A bit like the above.

         Exhausted stop - leads to a purple tone to the white areas of the print.

         Exhausted fix - the slow brownish toning of the finished print in day light.



Related Posts:

Monday, 19 March 2012

Prints to hard or to soft.

High contrast

What are the signs that a print has been printed to hard? The shadow areas are jet black with no detail and the highlights are blank  (the contrast is to great). Assuming that the negative being printed shows none of these traits then it can be corrected by the following:

         Use a softer grade of paper.
         Make sure that the exposure time is correct.
         The paper is in the developer for the right amount of time.
         Don't use a high contrast developer.
Low contrast
What signs make a soft print? It looks grey and foggy with little punch. No contrast. In this case it is almost the opposite to the above.

         Use a harder grade of paper.
         Increase the developing time. If the development time is to short it may cause cloudy spots.
         Make sure the developer is not too diluted.
         Also check that it is not exhausted. 

There are other possibilities:

         Your darkroom may not be light tight fogging the paper creating an overall grey cast.
         The paper maybe to old or has not been stored properly. 

Once you establish what the problem is, the cure will speak for it's self.

Related posts:

Evaluating your test strips
Darkroom fog.

Saturday, 14 January 2012

PMK Pyro after bath.


I have been developing Ilford FP4+ 120 format in PMK Pyro for ten minutes for quite some time, without an afterbath. With my latest use of this developer I decided to change part of the process, instead of inverting the tank every twenty seconds I changed it to every fifteen seconds to see if this increased the density of the negatives. My reasoning is that previous negatives have looked a bit on the thin side. Yes you are right! I could have increased the developing time but wanted to find out how much influence agitation has on the process.

FG 1
Film FP4+
When changing or adapting a method that works well, it is better to change one aspect of it at a time so that it makes it easier to judge whether it is an improvement or not. So what did I do introduce a re-bath of the film in the developer after the fix. The after bath is part of the full process when using PMK pyro that completes the staining. Up to now I have not felt the need to do this but was curious to see how much stain would be added and if it improves the print quality. I did this for the two minutes suggested which I agitated for thirty-seconds at the beginning and ten seconds one minute later.


FG 2
Film FP4+
There has been a marked difference in the density and the colour of the staining on the negatives. The picture marked Fg 1 shows the negatives developed with the afterbath, they have a yellow-brown look to them. Fg 2 shows negatives without the bath and they have a purplish look to them.

These results would suggest that an increase in agitation has just as much effect if not more on the density of the negative than an increase in the process time. The afterbath also produces a significant change in how much stain is deposited which is supposed to help in making these negatives easier to print. I have found that even without the extra staining I have been producing some wonderfully toned photographs. I have not printed this latest set of negatives yet but hope to do so soon.


Related Posts:

FP4+ PMK pyro method update.
PMK Pyro developer part B
PMK Pyro working solution

Sunday, 8 January 2012

Idiot list!


I've been clearing out the closet that I use as a darkroom. Whilst I was moving out some old photographic paper the bottom of one packet opened and on to the floor dropped a clear plastic folder. To my surprise it's my original film processing list; a step by step reminder for the developing process, showing what quantities to mix and how long to develop each of the makes of film. At the time it was Ilford PanF, FP4 and HP5. The developer is the recently reintroduced Paterson Aculux. The only film from the list to stand the test of time is FP4; the only film I use from Ilford regularly and remains my all time favorite.
When starting on your journey to develop your own film it is a good idea to make up an idiot list. It is there in writing to prompt you on what to do next; it is a way of ensuring that the process goes smoothly and that the negatives are properly developed. As you become more proficient you should update your list with the changes you make - ie: film development times, solution quantities etc. I still use one but now it's divided into two. One page shows the developing method needed for each of the developers I use and page two is a prompt for the stop, fix and wash procedure. I know it backwards but old habits die-hard.
So what has changed over the years? The developer for a start. The stop time has increased to two minutes. I no longer check to see if the film has cleared and the milkiness has gone after two and a half minutes when fixing. I had forgotten that I even did this! The wash time is down to fifteen minutes and I do not add fourteen drops of wetting agent - thats way to much!


Wednesday, 28 December 2011

First Rule of printing


The first rule.

Printing stark black and white enlargements will not hide a lack of technical experience. You should develop your printing technics to such an extent that it improves the expressiveness of your photographs.

Sunday, 25 December 2011

Test results for Agfa APX 100.


When taking pictures for the test it is best to choose a subject that is evenly lit. This will make the light reading more representative of the whole picture area. Unlike a high contrast view with deep shadows and strong highlights forcing you to take several light readings to find the average setting. It also makes it easer to evaluate the negatives once processed.
The processing of the film went well having spent all morning shuffling developing tanks, measuring jugs and developer bottles, the three strips of film have all been consistently processed. I am very pleased with the density of the negatives, when dry I will do a contact sheet so I can judge how well they will print.

You can see from the picture above, that the 13 minutes development time that digital truths massive dev chart suggests, is spot on. The results also show that you really do need to make a total and utter mess of things before you get a negative that will not print.
The light meter read negative at the centre
of the test strip.
There is a general guide to check whether a film has been correctly exposed and developed it should produce a continuously toned negative. The subjects deepest shadow should be perceptibly heavier than the clear of the film base. The areas that represent the brightest important detail in the negative must not be so dark that you can not read the printed words of a book through them on a sunny day as shown right. Its a quick way of checking to see if your negatives have been correctly developed.



The picture below shows the prints produced by the light meter read negatives in the centre of each of the test strips.

The difference between the top and centre is one and a half stops. bottom and centre is three-quarters of a stop. It is obvious that the longer you develop the less return you get for the time spent. Meaning that you will only get a slight improvement in the quality of your negatives for each minute of extra process time you give them over thirteen minutes.
These tests represent my own personal experiences I strongly encourage each individual to check this film out for themselves. The experiments I have carried out are not exhaustive and should only be used as a starting point.






Related posts:

Sorting out the test strips

Thursday, 15 December 2011

Drying agent?


This is the final thing you do before hanging up your negatives to dry. This helps with the drying process by reducing the water tension allowing it to run more freely and minimising drying marks caused by the lime in the water.

Add three or four drops of wetting agent to the developing tank. Agitate the spiral in an up and down motion for a few seconds and leave for a minute. A further refinement is to add wetting agent to de-ionised water and transfer the spiral to it. Take the spiral out and peal the film from its grip or separate the two halves whichever you find easiest to do.

Wednesday, 14 December 2011

Washing your negatives


This is just as important as the developing, stop bath and fixer. The temperature of the water needs to be close to that of the previous process of 20 degree C.

The purpose of washing is to remove the last of the fixer from the emulsion and needs to be done thoroughly to ensure the longevity of the negatives.

Which method to use? One way is to empty the tank and refill with fresh water and agitate for a few seconds, this should be repeated several times. Another way is to use a wash hose that is specially made to fit into the top of the developing tank and attached to the tap. I personally favor this approach with my own refinements: after fitting the hose in place I open the tap till it is nearly fully open and leave for thirty seconds, this vigorusly removes the last of the fix that remains. Then slow the flow right down for the next ten to fifteen minutes. It is a simple straight forward procedure that has served me well over the years.

Tuesday, 13 December 2011

Stop bath


Does what is says on the bottle! It is used instead of a wash as it helps to prolong the life of the fix and stops the developing process straight away. You must be careful not to contaminate the developer with stop, it will destroy it.

Stop can be obtained in two types of concentrated solution. One is odorless made from citric acid and the other acetic acid with a vinegar smell which can be quite pungent if used for prolonged periods in the darkroom, when processing prints in trays. Both have a colour change indicator added to the solutions so you can tell when it is exhausted.

Dilute the concentrated Stop one part solution to nineteen parts water (or as instructed on the bottle.) say 50 mls stop to a litre of water with a process time of one to two minutes, you will not gain anything by extending the stop time it is most active in the first few seconds. Agitate for the first thirty seconds, this ensures the developer has been completely deactivated, then ten seconds in every minute if you stop for two minutes.