Thick emulsions : LUSENET : B&W Photo - Film & Processing : One Thread

I have a question regarding thick (double) emulsion films. I know that this kind of films contain two emulsions, one fast, and one slow. But, do these two emulsion develop at the same speed? IS it possible to overdevelop on emulsion and underdevelop the other? How would this effect the film curve and tonality? I use Fortepan and Verichrome mainly and I want to get the best of them. I noticed that these films render better tones when they are developed to a density above the average. I was searching the net for any articles regarding this kind of emulsions but I didn't find any!

regards xosni

-- Xosni (, January 01, 2002


I do not beleive that you are correct when you state that "thick emulsion" films are those that have two emulsion used in their manufacture. Many films mix multiple emulsions to enhance speed or contrast characteristics. Thick emulsion films are simply those where the physical thinkness of the emulsion is larger. If I remember correctly these films will respond more strongly to changes in developer times and dilutions.

-- Ed Farmer (, January 07, 2002.

I've heard that the 35mm FP4 and HP5 plus are made with a two emulsion mix, but I guess they just mix them before they coat the stuff on the film base. They would be able to manufacture a film with double coating, but I don't know if it would help for anything, on the contrary I would guess it would be bad for the general acutance of the image. Maybe our friend from Ilford could help us on this point...

-- George Papantoniou (, January 08, 2002.

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