Echanges sur tous les aspects du labo photo argentique couleur : matériels, développement des films couleur, tirage, etc. Présentations des labos photo argentique couleur.
Bonjour,
Je vais bientôt acheter quelques feuilles d'ilfochrome et je suis à recherche d’informations sur son développent.
Sur wikipedia on peut lire ça:
Le processus de tirage Ilfochrome commercialisé pour les laboratoires amateurs (P30) comprend cinq phases :
- le développement par un révélateur noir et blanc conventionnel,
- un premier rinçage à l'eau,
-le blanchiment par bain d'acide pour enlever les pigments ou agents colorants non exposés,
-le fixage de l'épreuve,
-le lavage de l'épreuve à l'eau, généralement court à cause du support tri-acétate et non papier.
Le développement noir et blanc peut être fait avec du PQ universal?
Le fixage avec du rapid-fixer?
Ilford Ilfochrome P3V (P-30) - Ilford is no longer able to produce powder chemistry since Mobberley stopped production. As a quick fix, they have introduced a Kit 3.5 (based on P3 chemistry used in professional labs). With the introduction of the new bottle (with child proofed caps), they will re-introduce a P30 kit in 2-litre size (planned with sulphuric acid but easy to convert to old acid)
P30 or P30P chemistry used a different type of acid than P3. However, the ready to use solution contains more or less the same ingredients sulphamic acid + p-Toluenesulphonic acid or Sulfuric acid + 7K + Ludigol 100° + KI and Bleach accelerator
The Bleach of the Kit 3.5 contains about 33% sulfuric acid, which is totally different from the point of view of hazard
p-Toluenesulfonic acid is an organic compound as a white solid that is soluble in water, alcohols and other polar organic solvents; TsOH is a strong organic acid, about a million times stronger than benzoic acid; It is one of the few strong acids that is solid and, hence, conveniently weighed; Unlike some other strong acids, TsOH alone is non-oxidizing
From Ilford's experience in developing P30, P3, P3X or P5 processor, the bleach temperature is the critical factor for metallic part corrosion; Therefore, Titanium was recommended for building equipment in contact with sulfuric acid as soon as the temperature exceeds 32°C
After a long search, the patent appears to be missing from the folder. Isn't that always the case?
Anyhow, I found a generic dye bleach without all of the variations in another patent. Here it is.
quinoline 50 ml
Sodium hypophosphite 5 g
Potassium Iodide 10 g
Sulfuric acid conc. 75 ml
Water to 1 liter.
I have seen phenazine and phenazine derivatives used in this type of bath at from 10 - 100 mg / liter instead of quinoline. The other patent gives the list and concentration ranges. I always used phenazine.
I have also seen the catalyst added to the developer to promote uniformity in bleaching.
You can test the bath by mixing it, then fogging a small piece of dye bleach paper and developing it, then bleaching it in the bleach bath above. It should bleach uniformly down to a whitish dmin. After washing, fixing and washing it should be a good white with no color cast. If the cast is cyan, then the bleach did not reach the bottom layer and is diffusing too slowly or is not present in high enough concentration and must be adjusted.
If it gives other color casts, there are real problems. Adding the catalyst to the developer can help in some cases. If that does not fix the problem, then you are using the wrong catalyst.
blanchiment:
catalyseur de blanchiment : dérivé de quinoxaline 1 - 3g
nitrobenzène sulfonate 2 - 11g
acide sulfurique ( % ?) 30 - 50g
iodure de potassium 8 - 16g
mercaptoalkyl-sulfonate 2,5 - 5g
éthyldiglycol 20 - 50g
pH 0,8 ! (je trouve ça très acide mais...)
fixage:
thiosulfate d'ammonium 150 - 250g
bisulfite d'ammonium 25 - 50g
NTA (moins poluant que l'EDTA) 1 - 1,5g
azurant optique (du type de ceux utilisés dans la fabrication de la pâte à papier) 0,5 - 1g
pH voisin de 7
ah oui quand même !
d'une façon générale quand un industriel abandonne un produit, il devrait passer en open source
ya un député ici ? !! si oui alors réveil mon gars!
or, you can use a permanganate bleach which is used in normal black & white print bleaching.
Potassium Permanganate 0.5g
Conc. Sulphuric Acid 5m1
Water to 1 litre
EDIT: Je ne suis pas sur d'avoir bien compris la partie qui présente le blanchiment.