Determining film speed in a hybrid workflow

[jp]

In my humble experience the same basic film speeds and development times for darkroom printing work well when scanning.

You might find this helpful: http://www.kennethleegallery.com/htm...g.php#scanning

Yes. Scanners are designed to scan normally developed film.

Ken's scanning instruction is excellent.

[Laminarman]

I did another test while waiting for the step wedge and BTZS book. Just 30 seconds longer development and a little bit more agitation totally blew out my highlights. I'm not so sure I like Delta in Rodinal but won't give up quite yet.

[Laminarman]

Scan a shot (with all image enhacements disabled) alongside an Stouffer T2115 calibrated transmission wedge.

Now you have an accurate densitometer. By comparing the grays in the image to the also scanned calibrated wedge steps you may know what density has every spot in the image.

Measure density in the not exposed areas, there you find the Base+Fog density.

If your EI speed is correct and development is Normal then:

> Spots in the scene metered at -3.3 will have 0.1D over Base+Fog,

> Spots metered +1 will have 0.9D over Fog+Base. (Also an spot metered at -/+0 should have 0.72D over Fog+Base)

These are your main reference points (metered -3.3 and +1) to know if contrast is Normal and if true Speed is ISO, following ISO rules.

With that you can check if your process is ISO normal.

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Let's see what you have to do if your process is not Normal and you want it Normal.

1) Make tests: Adjust exposure until spots metered at -3.3 have 0.1D over fog+base

2) Make tests: Then develop more or less until until spots metered ar +1 have 0.9D over Fog+Base

3) If you modified development time then repeat from point 1)


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You don't need to use the Normal processing and ISO exposure, but you may want to know the ISO Normal development/exposure as your reference point across different films/processings

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If you want powerful skills about practical senstometry then read Beyond The Zone System book, me, I've learned a lot thanks to it.

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Hybrid processing allows to deal with high densities that would be a problem for darkroom printing. So for Hybrid you mostly need to ensure that you expose enough to record the shadows. For darkroom printing you may also need to develop the right amount to not have excessive densities.

Pere,

I'm a little confused. The T2115 has .15 steps (1/2 stop) so am not following your math. But there is another issue I'm having using SilverFast and Epson V850, and that is when I scan the step wedge I see distinct steps up to about step # 14 then they are all the same white, without any further steps being distinguished. I'm using a profiled NEC monitor and have turned off all image enhancements in SilverFast. Any help there appreciated. I think I've successfully nailed down my ISO but with a washed out step wedge don't know how to proceed. My negatives look a bit over developed as my Zone VIII have little to no detail or texture. Rodinal 1:50 with Delta 100.

[Pere Casals]

The T2115 has .15 steps (1/2 stop) so am not following your math.

An step is not exactly half stop (but close), see this table: http://www.stouffer.net/T2115spec.htm

Epson V850, and that is when I scan the step wedge I see distinct steps up to about step # 14 then they are all the same white, without any further steps being distinguished.

#14 is just 2.0D, your scanner may see way, way beyond that density. You have to dig a bit about the scanning:

First you should not scan auto, go to Histogram and set scanning limits to take all the range.

Second you have to scan 16 bits per channel, and then save it in TIFF format, because if not you only will have only 8 bits per channel, this is 0-255 values that will deliver the effect you say. Scan 16 bits, configure Photoshop sampler to 16 bits and see 0 to 65535 values that will show you the differences in all density range.

Note that te image may look dull, because the scene/negative may have a larger range than the monitor, so you may see compressed tonality, anyway it would be good to check densities.

My negatives look a bit over developed as my Zone VIII have little to no detail or texture.

To know if you are making a Normal development see if the Z-VIII has the standard density from the Normal contrast.

Feel free to ask anything, here or in a PM. I'll be happy if I can help.

[Laminarman]

Thank you Pere. I didn't see that table on the Stouffer website. I'll double check everything i'm doing, I appreciate it!

[bob carnie]

I understand well enough about development and zones with shooting/developing. It's when it comes to scanning that it falls apart for me. I found with my Rodinal and Delta 100 I get a good Zone 1 with shooting ISO 80 and my method of development, in my tank, at my temperature, and agitation. How do I translate this to scanning instead of printing test strips in an enlarger? I scan in Silverfast on an Epson 850 with exposure set to "0". Any help appreciated.

I use a mac to drive both my scanners and in (library - I think) you can find a colour meter which can read LAB numbers or Greyscale for that matter.. Since L is luminosity and reads the image from 0 Black - 99 white you can use the meter to read the physical numbers. I think in ranges of 10 whereas the shadows start in the 0-10 L range, quarter tones 25-35 L range , Midtones 40-65 L range, 3/4 tones 70-80 L range and highlights from 80-99 L range.

Keeping i mind that there is fall off points for prints at both ends for different papers and process, for example when I am printing B W Silver on my Lambda I can get away with L - 4 for the shadow with perceivable detail in print( any lower number will print jet black even if you can see it through the transmission of your monitor), and 96 - L for the highlight with perceivable detail in print( any higher number will print total white even though you can see it through the transmission of your monitor). For inkjet BW these numbers change to L -6 and L-94 so there is a slight variance.

By understanding these numbers you can channel your knowledge of the historical 10 zone thinking and hold your two end points and then between those two points you can with Curves and other slick PS , Lightroom, Capture One methods create any kind of image you prefer from your original thoughts in exposing the film and development.

The camera stores usually talk about screen balance and nothing is farther from the truth, either the pixels will record on a certain process or they will not , any amount of screen balancing still has you shooting in the dark so to speak, but of course you will own a colour monkey or some kind of spectrometer which will give you the false sense of security that is so common out there.
By understanding this concept you can work at your scanning station with confidence.

[Laminarman]

This hybrid thing is tough for me, since I came from the traditional wet print. I just did what Pere recommended, and sampling my wedge in PS, I see there are differences in those steps but they are very small. I had not changed PS over to 16 bit in the mode option (but the color sampler still says "8 bit" for some reason). I seem to get the entire range scanned. My ISO is right at 100 for Delta, which by everything I read I'm an outlier since everyone seems to need to shoot with a lower ISO than box, but after three different tests, my development and agitation seem to peg me right there.

[Pere Casals]

T I had not changed PS over to 16 bit in the mode option (but the color sampler still says "8 bit" for some reason).

Let me repeat:

>> Scan 16bits, all histo range, don't use the "auto" button...

>> Save tiff format

>> In Ps click o the dropper and select 16 bits:

[Laminarman]

Pere, I'm not scanning in Auto mode. But in PS I do NOT have that option on the eyedropper to select 16 bit for some reason? I have the latest version of CC.

Forget it, found it. Thank you.

[Bill Burk]

Laminarman,

Everything is all right...

You see step 14 as the upper limit of density that your scanner can distinguish. That is the density above which your highlights blow out.

In terms of density, 14 steps is 7 stops. But in tone reproduction terms, with normal development you can cover a subject luminance range of double that (about 14 stops) which can be picked up by your scanner.

That's because you would usually develop your film to a contrast of about 0.5 to 0.6 where (in the straight line portion) film produces about a half stop of density gain per whole stop of greater exposure.

The "curve" would look kind of like a 30-60-90 triangle (Not a 45-degree triangle which would be a curve of unity which some ancient processes enjoy).

The normal scene is about 7 stops (5 in the sun from black to white plus 2 in the shade) plus there might be highlights that might blow out from being chrome, mirror or glass reflections.

So your overall system has 7 stops of latitude towards greater exposure as-is with a normal scene. You have the flexibility to develop to unity and still fit a normal scene. (You shouldn't unless you want to prove or demonstrate what is possible). You have the flexibility to expose an ISO 400 speed film at EI 6 and still fit a normal scene (You shouldn't unless you want to prove or demonstrate what is possible here too).