Thanks Matt. I had another look at David's negs but to my admittedly untrained eye the negs do not meet either of the two aspects of a weird mask colour or being unreasonably dense. Is there a section on any of them that has an object that meets being in the light and shadow?If the mask is a weird colour, and the negatives look unreasonably dense, the likelihood is much greater!
When one actually works with the scans, it reveals itself quickly whenever you have a subject that is both in the light and in shadow.
The mask is quite dense and extremely yellow, especially for a fuji film stock. But of course I had the benefit of actually having the negatives in my hands, so I could see this quite easily.weird mask colour
David's negatives are singularly lacking in such examplesIs there a section on any of them that has an object that meets being in the light and shadow?
The mask is quite dense and extremely yellow, especially for a fuji film stock. But of course I had the benefit of actually having the negatives in my hands, so I could see this quite easily.
Are the tiff files those on your #77 where you have what looks like negatives turned into prints of the same size? I cannot see any other negative sized prints or pics of the negatives sent by David. If these are the "as is" scans of the negatives turned into positives then of course these cannot be examined as negatives but interesting enough if these are the genuine "as is" scans of the negatives then in the red car scene the tarmac looks the same each side of the car which seems not to confirm the change in colour you mentioned you were getting in the big scanThe tiff files of the negatives are linked to in one of my posts above. They're scanned 'as is', but there's always the hidden magic of the scanner software at work. However, I think those files are as close to 'reality' as is realistically feasible.
Are the tiff files those on your #77 where you have what looks like negatives turned into prints of the same size?
In my opinion this has been a great discussion done by all parties in the way most investigative discussions should be done on Photrio and I don't think anyone sees your comments, Matt, as anything close to castigation of David
pentaxuser.
Sure, let me see if I can help.
....
(3) the set of 16-bit 'scanned as positive' TIFFs. I downsized these to keep the files relatively small (~20Mb each). If you require full res scans, let me know, I can share them via Wetransfer.
Set 3 (scanned as positive to 16-bit tiff, resampled to 50% linear):
Image #1
Image #2
Image #3
Image #4
On the contrary, what we are after is truth, not feelings. I appreciate ANY feedback from ANYONE. This is a positive attitude which will help us all. - David LygaDavid's negatives are singularly lacking in such examples.
The best example is probably the church, but even it isn't great (as an example for checking crossover) due to the harsh nature of the lighting.
If you look at the environmental portrait I posted, you can follow the subject's skin tones from highlighted forehead to shadows under the chin. As you do so, you will note no change in hue. If the source had been suffering from crossover, the hue would have changed.
And by the way, I looked at the tiffs of the negatives themselves that koraks linked to. I would agree that they are quite dense, and really yellow.
I'm not trying to castigate David for his approach - just caution those who might wish to apply it, if they are expecting negatives that are free of crossover.
Are the tiff files those on your #77 where you have what looks like negatives turned into prints of the same size? I cannot see any other negative sized prints or pics of the negatives sent by David. If these are the "as is" scans of the negatives turned into positives then of course these cannot be examined as negatives but interesting enough if these are the genuine "as is" scans of the negatives then in the red car scene the tarmac looks the same each side of the car which seems not to confirm the change in colour you mentioned you were getting in the big scan
Matt, I am unsure if your post is confirming or otherwise that my reference to koraks #77 is correct. What I was trying to say is that the only pics of David's negatives were those made by David. There are no other pics of David's negatives? If that is the case then short of the digital pics of the negs I am unsure how we judge your comments on the signs of crossover such as yellow cast or density
Thanks
pentaxuser
We could more easily see the effects of crossover, mask errors, and the process in general if two sets of negatives and prints were made, one with the standard process, and one with the diluted process, and compared them side-by-side, with skin tones and a gray scale included in the subject matter. Any tests made of this or any non-standard process should always include a grayscale, IMO. It easily shows any crossover.
With respect to that other thread, I think there is a good chance that the crossover we saw initially arose at the scanning stage, rather than the film exposure and development stages.Frankly my agnostic view has not been helped by another thread where crossover once again reared its head where the reason seemed to be largely connected to gross over-exposiure of Ektar but where on asking questions of the OP it appeared that little or no over-exposure took place and the film was developed by standard commercial C41 development. Frustratingly that discussion just seemed to fade away
We could more easily see the effects of crossover, mask errors, and the process in general if two sets of negatives and prints were made, one with the standard process, and one with the diluted process, and compared them side-by-side, with skin tones and a gray scale included in the subject matter. Any tests made of this or any non-standard process should always include a grayscale, IMO. It easily shows any crossover.
A good point, RPC, in respect of your suggested test.. My problem which you may have gathered is that what I look at governs what I see and what I see depends on what I look at.
In my entire 70 years I have yet to hear a response as targeted, succinct, and all-encompassing as this. - David LygaThanks Mr Bill and I agree that RPC's test is a pretty good test of the existence of colour crossover. In my case I haven't come to a conclusion but would like to try to do so and so far I have found this difficult with what appears to be conflicting evidence.
What concerns me to an extent and this is even more concerning in the other thread started by Bormental about Ektar, is that if there is a problem in a scan which fails to conform to what another person believes is what it should look like then the fallback is to cite colour crossover as the cause without suggesting a route by which to navigate to the truth or being prepared to answer perfectly reasonable questions asked by what they seem to regard as "upstart crows" instead of saying to themselves that these are questions that deserve answers that can cover what has been asked.
The problem with colour crossover is that without a rigorous route to examine and test the truth of whether it exists or not in a negative is that those who may admittedly have a lot of experience of C41 development and believe they know the cause which usually is that of the fallback cause of colour crossover, end up answering the disinterested outsider's questions with the kind of answers which border on saying it is a form of science that is a little like alchemy that only a few of us are given the privilege to understand.
pentaxuser
Crossover is a fault.Thanks Mr Bill and I agree that RPC's test is a pretty good test of the existence of colour crossover. In my case I haven't come to a conclusion but would like to try to do so and so far I have found this difficult with what appears to be conflicting evidence.
What concerns me to an extent and this is even more concerning in the other thread started by Bormental about Ektar, is that if there is a problem in a scan which fails to conform to what another person believes is what it should look like then the fallback is to cite colour crossover as the cause without suggesting a route by which to navigate to the truth or being prepared to answer perfectly reasonable questions asked by what they seem to regard as "upstart crows" instead of saying to themselves that these are questions that deserve answers that can cover what has been asked.
The problem with colour crossover is that without a rigorous route to examine and test the truth of whether it exists or not in a negative is that those who may admittedly have a lot of experience of C41 development and believe they know the cause which usually is that of the fallback cause of colour crossover, end up answering the disinterested outsider's questions with the kind of answers which border on saying it is a form of science that is a little like alchemy that only a few of us are given the privilege to understand.
pentaxuser
Is there a principled method for detecting and measuring colour crossover in colour image processing literature? Strangely I couldn't find anything on this subject on google scholar which makes me wonder if this phenomenon has a different scientific term. There are a couple of patents that mention anti-colour-crossover agents in colour emulsions but there's not much discussion on what they do.
Thanks David for those kind words.In my entire 70 years I have yet to hear a response as targeted, succinct, and all-encompassing as this. - David Lyga
I think I have an idea why you are having a problem with this.on most other situations short of a picture of a Macbeth chart any colour crossover can be near impossible to detect unless you were the taker of the picture and have a very good memory of what was there in terms of colours and what the actual shadows were like in terms of colour changes
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