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.

Silverproof paper

This is the second run of budget priced paper marketed by Silverprint and has a matt finish. The first run was gloss. I have used the later and was impressed with the photographs it produced. With its grades being limited to two I was not put off.

Ilford FP4+,120 fromat 6x6 negative, Developed
in PMK Pyro and printed on
Silverproof paper Matt.

I originally purchased the gloss paper for contact prints and didn't really take much notice of how well they were being produced until I obtained a 12 x 16 slottie (Nova paper processor. which was the dirtiest bit of kit I have ever purchased second hand, a story for another post). The silver proof paper was the largest sized paper I had on the shelf and I was  impatient to see how well this new piece of kit worked. I was surprised by the tonality of the paper which lead me to make a series of photographs. It is a shame it was a limited retail run. It will missed.

Then a second batch was announced on Matt paper, which is a finish I'm not a fan of, but I'm always happy to try something new. This will also be a limited retail run, so if matt is your preference get some boxes in while you can.

Ilford FP4+ 120 Format 6x6 negative, Developed
in PMK Pyro and Printed on
Silverproof paper Matt.

The paper is completely different from what I'm used to. It is difficult to tell which is the emulsion side in the darkroom but with a little practice, the back has a slight  fibre feel to it which takes a time to get the hang of. First impressions are good, the photographs remind me of the cover page to Black and White Photography magazine in the way it looks and feels but has a depth to it that ink cannot replicate. It also does not have that richness of tone you get with gloss papers. Having said that, I like the difference and  expressiveness  it gives to the pictures it produces.   

Ilford FP4+ 120 format 6x6 negative, Developed
in PMK Pyro and printed on
Slverproof Paper Matt.

The pictures that complement this post were developed in a warm tone developer from Ilford with the enlarger set at grade two, initially it was set  at  grade three but I found that the pictures had to much contrast. On hindsight it may have been better to use an un-toned developer, but then I was not planing to use the proof paper for a full print session. I got carried away after the first test prints and I'm pleased I did.

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.

Evaluating your print test strip.

low contrast

High contrast

correct contrast

Now that you have your test strip what are you looking for? You are looking to see which of the timed sections gives you blacks that are really black without making the whites look grey, with a good separation of the greys in-between. If the picture looks grey overall with no defined blacks then the paper grade is too soft, meaning lack of contrast. On the other hand if the blacks dominate the picture then the grade of paper is to hard - too much contrast! If you need to change the grade of paper you will need to make another test strip. It should be noted that test strip evaluation is best carried out when they are dry as wet ones tend to hold back some of the more subtle grey tones which may encourage you to pull or push the expose time needed. While checking this you should also be ensuring that the focus is accurate.

When your test strip is pin sharp with good clear highlights, defined shadows and the right amount of contrast, you are ready to make a print.

Photographys. Bigger again?

To make enlargements over 50 x 60 centimeters requires a different working practice and a large darkroom.

If your negatives allow you to print them at 50 x 60 centimeters this is not the end of the story, you can go bigger with roll sized paper of 65, 100 and even 130 centimeters wide. But to go larger you will need a different method to produce them and a larger negative to start with which will increase the quality of the image projected by the enlarger. Your darkroom will need to be big enough to cope with the increased size of equipment. You will need an area of clear space that the enlarger can project the image onto whether it is the floor or a wall. Of the former the latter is the better way of doing things as you are less likely to get dust on the paper, it also makes it easier to dodge and burn if you need to.

Agitating the developing tank.

The main reason for inverting the developing tank is to make sure that the film gets equal treatment in the developer. One of the best ways of achieving this is to tumble the tank by turning it from end to end.

Why do we agitate the tank? The developer interacts with the emulsion of the film. It vigorously attacks the silver it come into contact with and becomes exhausted. By inverting the tank you refresh this action, producing evenly developed negatives. It is

important to get this right. To little agitation will allow by-products of the process to build up, leaving pale-toned streamers as they slide to the bottom of the tank. Likewise excessive inversions will produce currents in the developer, creating uneven development. Most process times allow for agitation.

Once the developer is added you should agitate the tank for the first thirty seconds but before you put the tank down give it a slight twist and tap it on a hard surface ( it is a good idea to lay a soft towel down so you do not damage the tank) so you dislodge any air bells/bubbles that may have attached themselves to the film. Then you need to agitate for ten seconds in every minute of the process time about four inversion per ten seconds or as the developer manufacturers instruction advise. For example PMK Pyro recommend one inversion every fifteen seconds. 

I have used this inversion method from the start of my developing career ( no pun intended) and has produced consistent results every time. Once you have found a method that works for you; you should stick to it.