Digital BW, The Print

David;

I run a studio here in Boston called "Artslides". Every day I shoot 
35mm slides, 4"x5" transparencies and digital files of 2D and 3D 
artwork for individual artists, galleries and publishers. I photograph 
oil paintings, watercolors, drawings, B&W silver prints, c-prints, 
inkjet prints... just about every medium you can imagine.

There are several reasons why your slides came out with a color cast 
and did not match your Ultrachrome prints. The biggest reason by far is 
the fact that you used a dimmer on your 3200k Tungsten lights. As you 
dimmed the lights the color output of the lights warmed up a lot 
resulting in the slides with a warm color cast. If you re-shoot the 
slides with the lights on full power and adjust your exposure 
accordingly you will get much better results. However, there are still 
some other factors you would need to take in account to get a perfect 
color match from prints to slides.

B&W prints made with the Epson 2200 and standard Epson driver do 
exhibit metamersim. The metamerism is not as severe as prints from the 
2000P but the metamerism is still there. So when you illuminate the 
prints under tungsten lights they tend to warm up magenta or red. 
Typically when I photograph 2200 prints I need to add 5cc to 7.5cc of 
green using Kodak gelatin color compensating (cc) filters in front of 
the lens.. B&W prints are the hardest to match on slides. Any slight 
color shift will be obvious. Color images tend to hide small color 
shifts.

The type of film you use, your lights, your lens and your lab's E-6 
line are all have slight to significant color biases. The only way to 
get a perfect dead on color match from prints to slides is to shoot a 
test of your subject with a standardized setup. Process the film, 
evaluate the results and then use color compesating (cc) filters over 
the lens on your next shoot to counteract any color cast / bias.

I hope that helps!

-Jeff




On Thursday, November 6, 2003, at 12:13 AM, David Wroblewski wrote:

> Hi all, I had a strange experience today and I need some
> advice. I discovered a public art opportunity in my area with
> short notice last week. They require 5 slides of my
> prints for judging. These are B&W prints made on a 2200 with
> the standard UltraChrome inks, standard Epson driver.
>
> I'd never shot slides of prints before, but I decided to set
> up my 35mm Nikon and shoot a roll of Ektachrome 64T tungsten
> balanced film. How hard could that be? I closed the vertical
> blinds, taped the prints to a black matt board & hung them on
> a wall, set up a couple of tungsten photo lights (3200K)
> (not strobes) and exposed 36 slides for 1/4 second, based on
> my spotmeter reading (with some aperture-based bracketing to
> cover my bets.) No filter on the camera or in front of the
> lights.
>
> As far as I understand, this is all standard operating procedure
> for photographing flat artwork. Though as I say, I've never done
> this before.
>
> I just picked up the slides. They were exposed correctly, but
> every one has a deep magenta cast. The prints looked nicely
> neutral to my eye when shooting.
>
> I could shoot another roll of slides, but I don't understand
> what I ought to change. Is it possible this is a function
> of metamerism in the UC inks that only appears on color film?
> (That sound ridiculous to me--I'm embarrassed to even state the
> question. But there it is.) Has anyone shot slides of UC prints
> as described above and got neutral results? Or can someone guess
> from the above description what sort of dopey mistake I made?
> Could the lab that processed the film have screwed them up
> somehow?
>
> Thanks for all advice,
> David
>
> ps. I know I could find a service bureau to print the slides
> from a digital file, or use Scala, but I thought this would be
> both cheaper and faster. In the future, when I have more time to
> prepare, I imagined I would use Scala.