Kodak Aerocolor (2460) compared to Ektar 100 in 120

dokko · Nov 22, 2023

I'm still not sure if I understand properly...

you mean, that if we scan two films on the same scanner with the same settings, we can say acurrately what the differences between the two films are when scanned on this specific scanners with those specific settings?

If so I see your point and totally agree.
I'm just not sure how helpful this is if the results both look rather unpleasant because the scanner settings are unsuitable for the films.

sorry for being a bit slow, maybe it's a language thing (I'm not a native english speaker) or I'm missing something obvious.

albireo · Nov 22, 2023

dokko said:
If so I see your point and totally agree.
I'm just not sure how helpful this is if the results both look rather unpleasant because the scanner settings are unsuitable for the films.

You understand correctly. What we disagree on is on what 'helpful' means here. The methodology suggested above would only be used to establish a set of ground differences given your constraints. I personally think this is helpful. This methodology wouldn't be used to find an absolutely or generally 'pleasant' result.

If the observations drawn from the method above led you to decide that what you see is generally unpleasant, then one could of course go ahead and start replacing variables, (one at a time!), followed by a completely new set of tests.

For example, dump the old scanner, get a new scanner in, repeat the experiment.

If you had decided, on the other hand, that all scanners are unsuitable for reproducing C41 negative colour, then of course all there would be left to do is to abandon any experimentation and move on to do colour photography with a different set of tools (fully wet workflow? fully digital?) etc

dokko · Nov 22, 2023

ok, I get it now

albireo said:
For example, dump the old scanner, get a new scanner in, repeat the experiment.

or get another standardised color inversion method

ps: this was written tongue in cheek, but there's a serious issue behind it:
without a color conversion specially calibrated to both, a specific scanner and a specific film, you can buy as many different scanners as you like and never get really good results.
and as mentioned in an earlier post, Ektar is one of the films which most scanners render poorly because it's quite different than other films and the scanners don't offer a specific color inversion method tailored to it.

it's also one of the problems that programs for camera scanning face:
unless we know which camera was used for scanning, which backlight, and which film it will be impossible to build profiles that match well.

albireo · Nov 22, 2023

We seem to be talking about a few unrelated issues. Sorry I'll stop here if that's ok.

brbo · Nov 22, 2023

Now I'm intrigued. Obviously not exactly the same lens and same time of day, but I really wonder what conclusions you can draw from applying "standardised inversion algorithm" on a scan of Aerocolor + Ektar 100.

koraks · Nov 22, 2023

brbo said:
a scan of Aerocolor + Ektar 100.

I know this probably sounds sour, but at this point I'm always out and go do something else:

brbo · Nov 22, 2023

@koraks does the link work now?

koraks · Nov 22, 2023

@brbo Much better, thanks! Sorry about the grumpy response.

koraks · Nov 22, 2023

So this is balanced for the Aerocolor:

This for Ektar:

Side by side:

It's all debatable of course how punchy it should be and how exactly you determine which color balance is 'correct'. I did this in a seat-of-the-pants way. I balanced the Ektar more contrasty than I normally would; you could take this in any of a million directions.

What this mostly demonstrates, at least for me, is that the inversion is still a manual process and especially the direct comparison between a masked and an unmasked film is really tricky.
The Aerocolor scan was certainly easier to balance than the one I briefly played with earlier in this thread. It helps to have the actual source before inversion etc. And it's really not a difficult scan to work on, IMO. The Ektar is a lot more challenging.

I'm sure if someone ran these through any of the nifty inversion tools they'd get nice results, too.

PS I just took a screenshot instead of downloading the tiff, so I worked with the low-res 8 bit version. You can tell from the Ektar shot which posterizes pretty horribly, but that's just a fluke. This would come out better if you work on the actual 16 bit original.

dokko · Nov 22, 2023

here's the same color inversion (a random one since my profiles are not calibrated for the scanner used) applied to both of the scans (which I understand have been done with the same settings), balanced for the top one:

brbo · Nov 22, 2023

Yes, there is no way around interpreting the negative. You have to do it when you print and when you scan. And there is no point in using standardised inversion with same parameters.

Would you regard Aerocolor as unusable if you printed it with the same parameters that make Ektar look decent?

Of course not. You change parameters to get decent Aerocolor!

lamerko · Nov 22, 2023

Hmm... looks like 2460 will be a very interesting film

albireo · Nov 22, 2023

brbo said:
Yes, there is no way around interpreting the negative. You have to do it when you print and when you scan.

If you're trying to invert simultaneously such different film material as the ones above, sure.

brbo said:
And there is no point in using standardised inversion with same parameters.

Disagree, in general. Starting with standardisation is always good, and the only real way forward when attempting to do a controlled test like what OP is doing.

Taking it it from there, and customizing further to taste, is of course entirely understandable.

dokko · Nov 22, 2023

albireo said:
If you're trying to invert simultaneously such different film material as the ones above, sure.

pretty much every film material is different, so the problem remains the same, it's just much less obvious.

even with the same film material, if it's old or has been processed at different days, you might for example have a green color cast in one of the film (or a magenta cast in the other, depending how you look at it).

sure I can now say, one film is green relative to the other, but this helps very little - which of the two is the "true" film color, the one with the green shadows or the one with the magenta shadows?

albireo · Nov 22, 2023

dokko said:
sure I can now say, one film is green relative to the other, but this helps very little - which of the two is the "true" film color, the one with the green shadows or the one with the magenta shadows?

The idea of running reasonably well controlled tests to find personal, reproducible parameters is not new in photography.

Are you familiar with the zone system? It's a proto-scientific approach to determining optimal film exposure and development strictly in your own workflow. There is no absolute 'trueness' coming from the zone system (what I find in my system is only valid in my system and not yours) and the same is the case with the controlled procedure I was describing to OP. There's not much more to it, really.

dokko said:
pretty much every film material is different, so the problem remains the same, it's just much less obvious.

even with the same film material, if it's old or has been processed at different days, you might for example have a green color cast in one of the film (or a magenta cast in the other, depending how you look at it).

yep. I know, right? Science is hard. But you need to start somewhere. And you're getting the gist of it. We could build a more complex model once we've tested the basic one, incorporating for instance a correction parameter for film age, and another for film batch variance!

But seriously - if we don't want to employ a little rigour, the best thing to do is just to shoot the cheapest common denominator film and send the negatives to Dokkoscan so that you'll perform some magic post-scanning.

After all, some people think that with a sufficient amount of photoshop tinkering everything can be achieved - is this your key take home for OP?

dokko · Nov 22, 2023

well, I think the OP has enough information about different approaches to make up his own mind how to proceed and I don't see much point in arguing about something we clearly disagree.

brbo · Nov 22, 2023

albireo said:
Disagree, in general. Starting with standardisation is always good, and the only real way forward when attempting to do a controlled test like what OP is doing.

Might be just semantics.

Both my examples are a product of the same routine. But parameters for certain parts of the routine are not the same. They can be computed by limiting the area of the non-inverted image that is used for analysis or controlled by a human (same as when printing). With that, I consider every negative itself to be a set of parameters. This is totally different to matrix profiles or 3d lookup tables that are precomputed transformations that are used (with more or less (usually) success) for slide film.

DREW WILEY · Nov 22, 2023

Ektar has some inherent blue/cyan confusion issues. Under sample shot condition this thread began with, a pinkish skylight filter should been used, like a 1B or KR1.5. That kind of issue is difficult to post-correct. It should be done at the time of the shot via proper filtration.

Split lighting, with some portions in deep shade under a blue sky, and other portions in warmer direct sunlight, poses a more complex but solvable problem. I have commented on these issues many times before, so I suppose the search feature concerning Ektar threads could be used. It's a film I'm highly familiar with.

The "Zone System" won't help this question whatsoever. It's color-blind. But I can state that Ektar as more limited latitude than most color neg films, only about a stop more on either side compared to slide film at most. Get very far out of bounds, or meter carelessly, and hue accuracy drops off pretty fast. Use 100 box speed. Otherwise, with a bit of care, it's probably the most color-accurate across the board color neg film. I does need to be properly color temp balanced with appropriate filtration to obtain that neutrality, however.

Romanko · Nov 22, 2023

koraks said:
the orange mask on C41 film is partly density-dependent on two out of the three dye colors

This is interesting. Can you explain this a bit more? Is this by design or incidental? Are there any tests that demonstrate the effect?

MattKing · Nov 22, 2023

Romanko said:
This is interesting. Can you explain this a bit more? Is this by design or incidental? Are there any tests that demonstrate the effect?

The dyes are not perfect. The mask is designed to correct the imperfections - it varies with the density of each dye.
The net result of the sum of dye plus variable mask is a corrected pair - the imperfections are essentially cancelled out by the variable mask.
The mask is of great benefit for the colour fidelity of colour negative film.

Romanko · Nov 22, 2023

MattKing said:
The mask is designed to correct the imperfections - it varies with the density of each dye.

Thank you. Are there any books, patents or papers that describe the variable mask in detail?

MattKing · Nov 22, 2023

Romanko said:
Thank you. Are there any books, patents or papers that describe the variable mask in detail?

Good question. My knowledge comes from a variety of sources - I'm trying to think if I can of something that organizes and collects that.

Romanko · Nov 22, 2023

MattKing said:
I'm trying to think if I can of something that organizes and collects that.

I use TiddlyWiki.

MattKing · Nov 22, 2023

Romanko said:
I use TiddlyWiki.

I was referring to a book or comprehensive printed article .

koraks · Nov 23, 2023

Romanko said:
Thank you. Are there any books, patents or papers that describe the variable mask in detail?

Why Colour Negative is Orange

Start here.

Kodak Aerocolor (2460) compared to Ektar 100 in 120

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