Base fog vs clear substrate films: is my logic flawed?

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Hi everyone...

I would like to bounce this off anyone interested.

I sell film here in South Africa, and I have had some feedback regarding the films coated onto a clear PET substrate. ie Rollei Retro 400s, 80s, etc.

Most of my clients end up scanning their negatives before editing and printing them. Pretty much the same as I do, since I don't have space for darkroom printing.

Basically, the issue at hand is that some clients have told me the Retro 400s and 80s films are too contrasty, specifically causing blocked shadows.
While I agree that the tone curve of these films is of higher contrast than others, the scans I have made ended up fine with plenty shadow detail.
If anything, the tones in the highlights are weaker than some other films.

Now, I scan on an Imacon 343, which is a fairly high end scanner, but most others scan on scanners such as the Epson V700.

The theory is, since Retro 400s and 80s are perfectly transparent, that these thin parts of the negative are recorded much closer, or further into the scanners highlight recording limit than that of films with a darker base fog.
Traditional triacetate films have a base fog with the thinest part of the neg being a few shades darker than that of the cleat PET films, and as a consequence there would be less highlight clipping when scanning, translating into better shadow detail.

Wouldn't traditional films be the better choice for scanning, or is my logic flawed?

Any input would be appreciated.

Regards,

Martin
 
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That is a great question!!! I hope someone has an opinion. My limited experience indicates a properly exposed neg should yield a good scan as the highlights and shadow areas should provide enough detail (limited only by the dynamic range of the film) regardless of type or color of the base.
JMHO
 
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True, a properly exposed neg is priority no.1! but.... I still think a neg with a clear base would require more DR from the scanner than the same scene shot on a neg with a base fog, specifically talking about the scanners ability to render highlights well (ie, the near black points of the actual image.) Whether or not this makes any real difference is another debate.

I hope this can provoke some technical feedback... I'm very keen to explore this, except I can't just go out there and buy another scanner :)
 
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Well, as no one else has stepped forward I will have a try.

Firstly I have no experience with the film type you mentioned. Last film I used extensively was either Tri -x or FP4. Second my film scanning has always produced satisfactory results for the limited amount of scanning I have undertaken both B&W and Colour - using a fairly inexpensive Epson V500.

What hit me the most was your comment 'too contrasty, specifically causing blocked shadows'. This would suggest, in the analogue days, overdevelopment. In this case the density of the highlight area so great that during printing to get detail here the overall exposure needed would cause the shadow detail to block (i.e. without dodging).

The blocked shadows and highlights lacking detail would be particularly apparent if using a condensor enlarger to print rather than a cold light/cathode source. The answer in this case would be to reduce developer action to control the density of the highlights while still retaining enough development in the shadow area. This may be achieved via reduction in development time, water bath technique, reducing agitation or a compensating developer.

So with all that said perhaps it is not too unreasonable to suggest that films intended for scanning should be exposed and developed to match the particular scanners response and limitations?

Traditional films may have a lower Film base + fog, from memory density should probably not really exceed .2 for most film developer combinations. So while it may make a difference to use 'traditional' films I suspect that the developer characteristics and correct development practice would have a much larger effect than change of film.

Then of course there are the choices to be made during the scan - Scan in RGB, Scan as Greyscale, Scan as Negative or Scan Normal and reverse in editing software - so many choices with different effects maybe?

EDIT: Sorry Fred you had posted while I was still ruminating
 
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Thanks for your reply.
I agree with you.

My opinion on the matter is, whether the my reasoning with base-fog vs DR is correct or not, is that there are other factors that will have a far greater effect regarding blocked shadows on scans.

I can't question the exposure and development procedure of this client of mine, but the only other possible factor involved in the workflow was the scanning phase. Also, the scanning software and editing manner will also greatly affect the outcome of the image, but my client seemed determined it wasn't due to the scanning workflow.

I just want to determine if a difference in base fog will determine better shadow detail or not for scanners with a more limited DR in the highlight department. I believe that there more important things to consider, because I dont believe the difference in base fog can cause large differences in results. I seem to think one needs to shoot and develop film for either printing or scanning. My client however pointed out a large difference in shadow detail from his previous film choice, while I haven't experienced a very large difference in shadow detail. Comparing Rollei Retro 80s and FP4, the 80s does have more contrast, but when developing it in Rodinal 1:50, I haven't noticed any troubles in the shadow areas.

If a scanner has a limited DR, I would think that development techniques would have to cater for this by creating lower contrast negs.
I am no expert at this, but I have experimented enough to know what different techniques and developers would look like when using my scanner, and I have seen some rather large differences.

I seem to think that the problem with too contrasty negs was fault to the software used.
My client was/is using the Epson software, and from what I have read (I have no practical experience here) Vuescan was much better.
This is what I recommended he use.
 
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...My opinion on the matter is, whether the my reasoning with base-fog vs DR is correct or not, is that there are other factors that will have a far greater effect regarding blocked shadows on scans.
Absolutely agree that factors other than base fog and DR will have a much greater effect.

I can't question the exposure and development procedure of this client of mine, but the only other possible factor involved in the workflow was the scanning phase. Also, the scanning software and editing manner will also greatly affect the outcome of the image, but my client seemed determined it wasn't due to the scanning workflow.
While I can understand that you may not want to question the exposure and development procedure of a client it does need to be looked at along with the scanning workflow. Seems like your client is not willing to admit any possible errors on his part and is blaming the film or the tools.

I just want to determine if a difference in base fog will determine better shadow detail or not for scanners with a more limited DR in the highlight department.
I would think that a difference in base+fog would have the obvious effect of decreasing the amount of light reaching the sensors and therefore possibly appear to lower apparent contrast and increase the density in this area. However by far the most important thing is, is there any detail recorded in the shadow areas in the first place either from exposure or to a lesser extent development?

I believe that there more important things to consider, because I dont believe the difference in base fog can cause large differences in results.
I believe you are correct here as I too cannot imagine that base+fog can cause that much difference.

I seem to think one needs to shoot and develop film for either printing or scanning.
Exactly my point. It is important to match the film characteristics by exposure and development to that which the printing or scanning device can handle.

My client however pointed out a large difference in shadow detail from his previous film choice, while I haven't experienced a very large difference in shadow detail.
This to me shows a fundamental misunderstanding by your client. We should choose film based on proper testing including personal film speed, developer choice etc. Presumably his previous film choice was well tested to arrive at a satisfactory film speed and development time for a particular developer - or perhaps he did no testing and just struck lucky and stuck with it :smile:

Comparing Rollei Retro 80s and FP4, the 80s does have more contrast, but when developing it in Rodinal 1:50, I haven't noticed any troubles in the shadow areas.
I used to use Tri-X in the main which was rated at 200 ISO (rather than the 320 - 400 ISO stated by Kodak) developed usually in Microdol X. FP4 always appeared to have more contrast and needed a different developer to produce acceptable results - not sure but I seem to remember settling on Perceptol for this with a slight loss of speed to somewhere around 100 ISO. The point I am trying to make here is that the developer (and development technique) can make a huge difference to the end result.
Your own testing with Rodinal indicate you have no issues. So in theory your client should be able to achieve similar to yours.

If a scanner has a limited DR, I would think that development techniques would have to cater for this by creating lower contrast negs.
I am no expert at this, but I have experimented enough to know what different techniques and developers would look like when using my scanner, and I have seen some rather large differences.
Absoulutely.

I seem to think that the problem with too contrasty negs was fault to the software used.
Not sure I agree with this other than the suggestion of 'too contrasty negs' in the first instance. Most software should cope pretty well with a wide range of contrast situations. I would think it more likely to be user error within the software leading to missing information - this assuming that the negative contrast and particularly DMax does not exceed scanner range.

My client was/is using the Epson software, and from what I have read (I have no practical experience here) Vuescan was much better.
This is what I recommended he use.
I have used both the Epson software and the Vuescan, both imo capable of producing excellent results. So far I cannot say that one better than the other. But I feel that the Vuescan (in spite of an old fashioned GUI) may be the easier to use for a beginner.
Final thought - Have you been supplied with one of your clients negatives and a scan to actually see what is happening in comparison to your own results?
 
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Sep 17, 2009
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Yeah, good, I feel a lot more settled now.

I feel the client may have been lucky with a previous combination of film and developer, which gave him better results for scanning.
The choice of film and chemicals here (excluding that which I import) are ridiculous. Basically only Ilford and some Fuji films, and ID-11 and Suprol developers. So I think the choice of Acros or FP4 and ID-11 were a good mix.

Anyways, I seem to get along perfectly with Rodinal and the various ways of using it...
Its only with some films that I need to consider other developers. However, I have decided to focus on what works in Rodinal.

Anyways, thank you for your input Tony. It was helpful!
 

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