Chaitanya Guttikar

Photographic Wetting Agents for film processing at home.

I see this kind of question very frequently being posted in forums.

Proper film drying after wetting agent use.I developed my first B&W film.  It’s developed ok but I got drying marks on the negative.
I couldn’t find Kodak photo flo or similar product in my city or online. My tap water is hard water. Is that a problem too? Please help.

How does a photographic wetting agent work ? : If you read the contents of a bottle of wetting agent, or their MSDS (material safety data sheets), you will find out that photographic wetting agents are nothing but a mixture of (more…)

Black and white film fixer times.

Sir John Herschel : Inventor of Sodium Thiosulfate Photographic Film fixer as well as the Cyanotype Process.For people beginning film processing at home, some of the common questions are “What is the correct fixing time for Agifix rapid fixer?” (or any other fixer), “Do I need to add a hardener in my fixer?” and “How long can I use the fixer working solution before it exhausts?”.

If you have encountered these questions, you are in the same boat as Sir John Herschel, the inventor of Hypo. But we now understand the fixing process much better and have more concrete answers to all these questions compared to Mr. Herschel. So here is our current understanding of things: (more…)

Better Shadows Detail / Highlight separation in Gelatin Silver Prints – Potassium Bromide.

Recently, I was asked if some tiny things could be done to adjust sharpness, increase highlight/shadow development, change grain size by fiddling with the chemistry that’s going inside the bottle while developing. More specifically,  the effects of adding Potassium Bromide (KBr) and and whether you might end up with some crispier images with bigger grain.

The answer to all the above questions is Yes. But in this post we will specifically talk about the KBr.

Potassium Bromide Crystals

Potassium Bromide (KBr) is a restrainer. As explained elsewhere, any film developer has four components : Developing Agent, Accelerator/Alkali, Preservative and Restrainer. The job of the restrainer is to prevent the development of grains that received no light (or very little light).

So, if you are getting excessive fog (more…)

Stand Development in D76 Developer Fiasco

Do you want to know if it’s a good idea to do Stand development in D76? And what dilution to use for that? Then here is the short answer.  In one line : DON’T DO IT! Based on my personal experience, various experiments and logic based on photochemistry-

I used 1:4 D76 in my 1500 ml tank that takes 6 negatives of 4×5 size as a first try. The commonly followed stand development procedure is 1 minute initial agitation followed by 1 hour (or time of your choice) stand with no agitation (True Stand development). I knew, even before I started, that being a solvent developer, D76 is not a good candidate for stand development. Actually, there are two reasons why it’s not a good choice but we will get to that. (more…)

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