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Wednesday 23 November 2011

Types of Enlarger Negative carriers


There are two main types of negative carrier, with and without glass. There are arguments for and against each type. Lets be honest there are three types, the adjustable.

Glass-less carriers avoid the Newton rings effect (a post for a later date) but also have the disadvantage of allowing the negative to buckle when they warm up, this is more pronounced with 6x6 negatives. To minimize this you should be very careful when focusing and use a smaller aperture to increase the sharpness across the negative.

Another disadvantage of a glass carrier is dust; to be honest it is not the big deal that everyone makes it out to be. It is just a case of being methodical in your approach. The main advantage of glass carriers is that they keep the negative flat. Another plus is that you can experiment with unusual effects by using various materials such as flower petals, salt crystals and soap suds etc in the carrier.


There are adjustable carriers also, which are very handy as they allow you to mask out badly illuminated edges without having to increase the magnification, or you can adjust them to include the rebate of the negative.

Enlarging Lenses



Enlarging lens mounted in lens saver.
When choosing your enlarging lens you should choose one that reflects the quality of the lenses you use on your camera. If you do not, that quality will not transfer to the final print. Of course there are other factors in play when making these decisions namely your own financial position; it maybe better to wait a little longer and purchase what you need instead of what fits your pocket at the time.

I cannot repeat this often enough that high quality camera lenses need high quality enlarging lenses, likewise reasonable quality camera lenses need reasonable quality enlarging lens. In other words like for like.

Enlarger


An enlarger consists of:

Enlarger for 35mmm negs
only. with out multigrade
head. Condenser type.

A baseboard on which enlargements are made; a column, which serves as a slide for the support arm, that holds the enlarging head, which consists of the lamp housing that contains the bulb; a single or double condenser; negative carrier, a place to fix the lens; a means of focusing and lastly a red filter that swings in front of the lens.

The lamp contained in the light housing is of the opal type and has a power output of 75, 100 or 150 watts. The pearlescents of the bulb with the help of a condenser distributes the light evenly across the negative. The lens focuses and projects the negative image on to the baseboard or rather an easel with paper on it. The higher the enlarging head is from the baseboard the closer the lens is to the negative the greater the magnification. The closer the head is to the baseboard the greater the distance the negative is from the lens the smaller the magnification of the picture. The typical focal length of lens for 35mm negative is 50mm and for a medium format (6x6) is about 75mm.
A multi format Enlarger with multi grade head.
Diffuser type.

The negative is clamped in the carrier which incorporates a mask that is the same size or format as the film and then placed in the light box. It is not a good idea to cut the negatives into single frames, it is better to leave them in strips to make it easier to line the frame up with the mask in the carrier, this also means you are less likely to scratched them.


Focusing is usually done manually, although there are enlargers available with automatic focus, these are usually more expensive.

Saturday 19 November 2011

Fox Talbot a short history to his discovery


William Henry Fox Talbot born 1800 died 1877.

Fox Talbot was considered a polymath some of his interests and qualifications included Philosophy, Mathematics, Physics, Egyptology, Philology, Syrian, Chaldean cuneiform text and photography. Fox Talbot carried out his experiments at the family home which was Laycock Abbey Wiltshire.

Fox Talbot's sketch of Lake Como
using camera obscura.
 

The idea of photography came to Fox Talbot while he was on a family holiday at lake Como Italy. He was using a camera obscura and Lucida to aid his fruitless attempts to sketch the lake ( Pictured right is a sketch drawn by Fox Talbot of lake Como using a camera obscura in October 1833) He put these devices to one side and thought back to a procedure he had used with a camera obscura that put an object on to a piece of paper attached to the back plate; this image did not last long it disappeared like a ghost in to the night. It was at this time that he thought it would be nice to fix the image permanently to the paper.

Fox Talbot started looking in earnest for a way to fix an image to paper in 1834; he would first have to find a paper that could be submerged in a solution of salt and silver nitrate without it disintegrating. The result of combining these two chemicals would make silver nitrate a light-sensitive salt that was not affected by the moisture in the paper. He now had a paper that could be used for photogenic drawing. The first pictures he produced were of leaves and lace. He placed these on a sheet of light-sensitive paper and put a sheet of glass over them, then left them out in the sun.


Fox Talbot used many different types of camera to produce his pictures. There we a couple of cameras or boxes that only measured two or three inches which Fox Talbot left around the grounds of Laycock Abby in different places with light-sensitive paper in for about an hour at a time. They were nick named mouse traps by the family. His early cameras would use telescope or microscope lenses.

This is the picture of the famous Oriel window in the south gallery of Laycock Abby. It is the earliest surviving paper negative dated 1835. when originally taken you could count the two hundred tiny pieces of glass that made up the window with the help of a lens. This is a replica of the camera he used to take the Oriel window shot.

By chance in 1840 Fox Talbot discovered when re-sensitizing some paper that the image had appeared; this became known as the latent image. Before this time he was having trouble with the sensitivity of the papers. Although he had been able to fix the images by using a strong salt solution of potassium iodine of hypo to stop the images fading. This new discovery was a major break through that meant exposures could be achieved in one to three minutes instead of half hour or more. The year after Fox Talbot discovered how to make his photogenic drawing process more sensitive to light by adding Gallic acid to the process. He also found that a further treatment of Gallic acid and silver nitrate would bring the latent image out. It was time he changed the name of the process to Calotype (from the Greek "Kalos" meaning beautiful) the Calotype was a negative/positive process introduced in 1841. Strictly speaking Calotype should have referred to the Positive part of the process.



The advantages of the calotypes were unlimited prints from one negative, retouching could be done to the negative or print, the paper print was easier to see and could be handled with out damage and had warmer tones.


Some of the draw back of this process were that prints tended to fade; fibers in the paper reduced the quality of the print, making the focus soft but some people found this an advantage. Materials were less sensitive to light needing longer exposure.



For more information:

Friday 11 November 2011

Wet side of the darkroom.


On this side of the room you will have laid out your developing dishes in the following order: developer, stop-bath, fix, print washer and/or sink. These may have heaters under them or you can have a slotty laid out in the same way. Obviously this will take up less space.
Typical wet side layout


This is where you keep your chemicals, it is also the place that the solutions are poured out and back into their storage containers. The height of this table needs to be right so you can work comfortably in the standing position. It is a good idea to store these chemicals under the table if there is a leak it will go on the floor and not drip into your working dishes ruining your prints. For safety reasons it is not a good idea to lean over your dishes to retrieve items from shelves above while your working as you may knock the contents of the dishes over yourself.

Remember that these chemicals need to be treated with care and you should follow the safety advice recommended by the manufacturer.

Safety in the darkroom


There are some health and safety issues in the darkroom. The most commonly used chemicals are no more dangerous than household detergents and bleaches, some of the more specialized chemicals can be hazardous. Here are some do's and don'ts to make things safer.
Do's
  • Wear gloves ( rubber or Latex), protective cloths and use eye protection.
  • Wash spillage's to skin and eyes quickly with lots of water.
  • Keep a tap hose for this purpose'
  • Clearly label everything.
  • Make sure there is good ventilation.
  • Dispose of solutions safely' seek advice if needed.
  • Mix chemicals slowly and in the right sequence.
  • Filter water and home-made solutions to remove bits especially for film processing.
  • KEEP ALL CHEMICALS OUT OF THE REACH OF CHILDREN.
Don'ts
  • Eat, drink or smoke when mixing chemicals.
  • Inhale dust from powders.
  • Fail to read instructions and warnings first.
  • Use kitchen scales for chemicals.
  • Use metal containers, mixers and trays.
  • Add chemicals together without knowing if the outcome is safe.
  • Add water to strong acids or alkali's ( e.g. caustic soda-Na OH). Always add them to water not the other way round and slowly.
  • keep large glass bottles on high shelves.

Dry side of the darkroom.


Typical layout for dry side of darkroom
This is the area where you will have your enlarger set up. The table will need to be large enough to allow for timer, puffer (like a rocket air) and magnifying glass. There will also need to be space for you to lay out your negatives, printing paper, scissors and or guillotine/rotary trimmer and holding back and burning in tools. It is a good idea if this area also has cupboards and draws for keeping your paper and equipment in.

Darkroom layout


When setting out your darkroom it is best to set your work flow from left to right. By doing so you are less likely to contaminate the dry side with chemicals or water. You should keep the enlarger table separate from the development table. The dry side takes up less space than the wet side so can be put along a shorter wall. The support for the enlarger should be completely stable and set at a comfortable working level when standing. For a standing position the right height is 95cm (37").
A typical lay out
Remember electricity and water don't mix so take particular care when providing power for your equipment. If in doubt consult an electrician. It is not imperative that your darkroom has running water but ventilation is and will need a light proof grate.

This may sound strange but make sure that the illumination is sufficient to allow you to see round the room when printing.

Saturday 5 November 2011

Developing tanks.


There are a number of well-known makes to choose from. The most popular and widely used is the Patterson system. Another and maybe not so well known is the German maker Kaiser no lesser a system. So what are the differences? When buying a universal developing tank, if cost is one of your main considerations the Kaiser system wins hands down as being very good value for money. So much so its worth considering if you are thinking of buying a Paterson second-hand.

Both systems have good and bad points to consider. Starting at the top in both cases I have found no matter how well the cap has been put in place it leaks slightly when inverting the whole tank. It can be a messy annoyance when using PMK Pyro as it stains whatever it drips on too. Yes I know that each system comes with an agitator but the Paterson one is difficult to use because it is so thin, unlike Kaisers which has a top to it you can grip and when turned also moves the spiral up and down in the solution as well. Each company uses a different way to fix their lids. Paterson's idea is a twist and click method which I prefer but can be miss aligned if you are not careful. The Kaiser tank has a screw top which I have managed to cross thread each time.

The Kaisers spiral design is the main reason that I have one of their developing tanks. I'm having trouble with kinking the film when loading 120 format onto Paterson spirals and have used lots of different ideas to overcome it. The main difference with the Kaiser reel is that it has two large feed in wings where you load the film which makes loading a lot easier and faster with no kinking. Because of the trouble I've been having with the Kaiser screw top tank I now use a Paterson tank with the Kaiser reel, it is a little loose on the centre tube but the C clip stops it moving up and down when inverting. So for now I have the best of both worlds.