Re: Using a 113 gray standard in digital photo
Re: Using a 113 gray standard in digital photo
- Subject: Re: Using a 113 gray standard in digital photo
- From: "Terence L. Wyse" <email@hidden>
- Date: Thu, 21 Dec 2000 10:41:10 -0500
Just thought I'd get it back to the original subject line. I hate those
"digest" subject headers :-)
Well, first off, I think you'll find a good bit of prepress folks are into
photography as the two are taught side-by-side in a lot of high school and
college graphic arts classes.
As for exposure, I'd still stand by that exposing for a 18% Gray Card will
ALWAYS give you the correct exposure regardless of the subject matter. Now,
if instead of metering the gray card, you are instead metering the scene
itself, of course if it's "80 percent dark or light values" you will need to
alter the exposure since the meter has no idea you're NOT metering off of a
gray card. If you're metering lighter tones, you will need to "overexpose"
accordingly and the opposite is true if the scene is low-key or mostly dark
tones.
As far as tonal range, I'm not sure if altering the exposure is technically
affecting the tonal range, I think it would be taking your "fixed" tonal
range and just shifting it up and down the scale. You'd need to be using
something like the Zone System to affect tonal range. With a digicam I'm not
sure if this is even possible as this was done traditionally by altering
film speed and either "pushing" or "pulling" the film during developement.
Maybe purposely changing the "film" speed rating in a digicam you could
affect the tonal range some but I doubt it.
Not to make too fine a point of it but I believe CORRECTING to a fixed value
in Photoshop would not be the same as EXPOSING for the correct value in the
first place, just as trying to correct for a bad exposure in the darkroom
when making a print is not the same as being correctly exposed in the first
place.
-Terry
on 12/21/00 11:31 AM, Jack Bingham at email@hidden wrote:
>
This is why printers should not be photographers, First you need to take into
>
acoount that each image may have a different tonal range. An image that is 80
>
percent light values will require a different exposure than one that is 80
>
percent dark values. Exposure is a highly subhjective issue that can not be
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distilled down to a specific set of values. Secondly, just because you match
>
the
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gray patches there is no guarentee that the colors will convert from rgb to
>
cmyk
>
in a linear fashion. Colors that are way out of gamut will require some
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modification. You are by no means crazy. Perhaps you either need another
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pre-press guy or you need to be making your convertions and color corrections
>
yourself.
>
>
Jack Bingham