Blindly believing something out of a book contrary to evidence sounds like a bad idea to me, and is fundamentalism.
https://www.latimes.com/science/sciencenow/la-sci-sn-human-eye-photon-20160719-snap-story.html
It would be at a density of almost 0,9, a bit below this. Keep in mind though that Dmin is 0,5 and this matters a lot. It's not the absolute value that is important, but relative to Dmin. I'll post some samples later, but it's rather hard to make them look the way they actually are, plus monitor settings will definitely skew whatever effort I put. So, take these samples with a grain of salt.@Anon Ymous: Nice work! Thanks for sharing. Do post some real-world examples when you have them.
If I read the graph correctly, Caucasian face would have a density of ~1 (by virtue of placing it in Zone VI). Wouldn't that look a little too dark in the slide?
See, that's the basic limitation of a public forum.And Grant is wrong.
Are you sure that, in this case Adox Silvermax is optimized for reversal processing?Even with a film that is supposedly optimized for reversal processing?
Are you sure that, in this case Adox Silvermax is optimized for reversal processing?
Being optimized for reversal doesn't mean that there must be no silver solvent in first developer.OP is interested in Foma 100 reversal film. You stated in another thread that the foma film is optimised for reversal processing. It's a bit of a travesty if thiosulphate needs to be used to get clear highlights for a film that's optimised for reversal processing. Of course you should do whatever works for you.
I have no idea why you are bringing in Silvermax into the discussion.
See, that's the basic limitation of a public forum.
Anyone can post anything he/she wants without being competent on the subject.
Do you are more competent than Grant Haist?
Do you have worked for Eastman Kodak as a scientist?
How many books on photography do you have published?
Please come back with some pubmed reference and then a discussion could be started.You're now using ad hominem to defend an untennable position, and that's an extremely bad argument on top ignoring the actual science. Established science has determined the sensitivity of the human eye quite well, any claim to the contrary is bunk. The more extraordinary the claim, the more extraordinary the evidence is required, especially when it is against settled science, it is like claiming the sun revolves around the Earth and quoting Copernicus and then if someone is more competent than Copernicus.
You know what, you're on to something here. I took a piece of the already processed film and dipped it in the permanganate bleach for 10'. Sure enough, it looked very clear after the metabisulfite bath. But then I cut it in half and placed one in the fixer and the other in D19. Few minutes later, it became obvious that the one placed in D19 picked up some density. I fixed this second piece as well and they're now drying. I guess I need to try with bleach mixed with sulfuric acid and see what happens.... Another doubt: does bisulfate contain impurities on form of halides? If so you will get a partially rehalogenating bleach.
You seem to be a great misunderstanding here. It is not my position that needs to be backed up, it is yours. Your position is absolutely ludicrous, as A) It has no evidence. B) It has no reasoning. C) It is completely logically flawed and D) It is completely against accepted settled established science. You need to turn to a mirror and ask yourself that, because your flat out rejection of basic science and fundamentalist mindset are quite worrying. You need to stop spreading this misinformation here. It is wrong. There is no discussion to be had about this, it is not an opinion, it is a matter of fact, it is flat out wrong.Please come back with some pubmed reference and then a discussion could be started.
Nature communications?
Are u kiddin' me?
My Greek friend: Greetings to you.You know what, you're on to something here. I took a piece of the already processed film and dipped it in the permanganate bleach for 10'. Sure enough, it looked very clear after the metabisulfite bath. But then I cut it in half and placed one in the fixer and the other in D19. Few minutes later, it became obvious that the one placed in D19 picked up some density. I fixed this second piece as well and they're now drying. I guess I need to try with bleach mixed with sulfuric acid and see what happens.
Any claim that says the human eye cannot see details beyond an optical density of 2.4 is absolute rubbish
Thanks. The sulfuric acid quantity isn't very important. Less can be used, but the bleach becomes slower while keeping better if I recall correctly. There's a patent posted by Lachlan Young somewhere, which describes this.My Greek friend: Greetings to you.
Successful permanganate bleaching needs 8ml of sulfuric acid to achieve a pH <1.4
Bleaching continues for a period of 2 minutes at a temperature of no more than 25 - continuous agitation without stopping, with changing the direction of the stirring (agitation) rotation every 30 seconds.
I don't need to be backed up at all. Just because I'm referring to well known and established photo literature that is published and wide available.You seem to be a great misunderstanding here. It is not my position that needs to be backed up, it is yours. Your position is absolutely ludicrous, as A) It has no evidence. B) It has no reasoning. C) It is completely logically flawed and D) It is completely against accepted settled established science.
Being optimized for reversal doesn't mean that there must be no silver solvent in first developer.
Who said that there's no silver solvent in Foma kit FD?
Just because it's not listed in the MSDS?
You can't tell the presence of silver solvent by just looking at the MSDS alone.
On the subject of thiocyanate, I'd like to point out that I didn't use any of it and got a Dmax of 2,35. The datasheet characteristic curve shows a Dmax of ~2,7. Using any thiocyanate will probably ruin it.What's your educated guess of the amount of silver solvent in Foma first developer? What's the maximum amount that can escape from getting mentioned in MSDS?
Very little since the FD is used as SD. Don't really know what's the thresold of any each chemical compounds to be put in MSDS.What's your educated guess of the amount of silver solvent in Foma first developer? What's the maximum amount that can escape from getting mentioned in MSDS?
The DMax is dependent not only to FD but also to second exposure and second FD, and to bleaches as well.On the subject of thiocyanate, I'd like to point out that I didn't use any of it and got a Dmax of 2,35. The datasheet characteristic curve shows a Dmax of ~2,7. Using any thiocyanate will probably ruin it.
Very little since the FD is used as SD.
If i had
a) bleached long enough
b) a bleach that didn't have a rehalogenating effect
then my minimum density would be better. In order to get a better maximum density, a lower fog first developer should be used. Perhaps some benzotriazole would make things a bit better.
Nope, it's not reagent grade, it's technical grade. Who knows what other stuff is in there. I'm aware of D67, I've used it in the past. It's not that D19/D67 is a bad developer in general. Fog can be a problem only when the Dmax of a film has a rather low value, as is the case of Fomapan R 100. So, perhaps if I used benzotriazole, I'd get a little less fog, so a bit more density. Fomadon LQR, being a PQ developer likely has some and is what is used as a developer in the kit.Is your sodium hydrogen sulfate not lab grade? Does it have substantial amount of chlorides as impurity?
Regarding base fog, you might be aware that Kodak D-67 is a well-known first developer in reversal processing of B&W film. D-67 is basically D-19 with some thiocyanate added to it. No benzotriazole was needed.
hypo 0,3g to 0,5g in 1 liter of fdOk, against the backdrop of this insight, how much thiosulfite/thiocyanate would you recommend @Anon Ymous to use in his D19 first developer for Foma-R film to get clear highlights? In your experience, what's the minimum amount of halide solvent that makes a real perceptible difference to the first development of a film like Foma-R?
watch out also the type of halide solvent you're using. Hypo gets you higher fog than DTODIf i had
a) bleached long enough
b) a bleach that didn't have a rehalogenating effect
then my minimum density would be better. In order to get a better maximum density, a lower fog first developer should be used. Perhaps some benzotriazole would make things a bit better.
Is the film expired? And if yes, how much is expired?Nope, it's not reagent grade, it's technical grade. Who knows what other stuff is in there. I'm aware of D67, I've used it in the past. It's not that D19/D67 is a bad developer in general. Fog can be a problem only when the Dmax of a film has a rather low value, as is the case of Fomapan R 100. So, perhaps if I used benzotriazole, I'd get a little less fog, so a bit more density. Fomadon LQR, being a PQ developer likely has some and is what is used as a developer in the kit.
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