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 10:08:12 -0500
Just my $.02 worth but what I think they're going for is the 18% gray card
(gray patch 3 roughly equals a Kodak Gray Card density of .74).
From what I understand, a Lab value of 47-48 equals the Kodak 18% Gray Card.
I did some poking around and in Adobe98RGB, a 113 is equal to this Lab
value. In ProPhotoRGB, this same Lab value works out to 92-94. I intend to
get my Spectrolino out soon and measure a few gray cards I have plus the
Macbeth Color Checker just to see for myself.
Seems to me a worthy goal to get the correct 18% Gray/Lab value on the Color
Checker given whatever your current working space is. This should give
correct exposure at least. Getting the "18% gray" placement/exposure right
is ALWAYS the correct exposure no matter what the subject matter. Incident
light metering will give you the same result.
Terry
_____________________________
Terence L. Wyse
PrePress Systems Specialist
All Systems Integration, Inc.
781.935.3322 voice
781.935.6622 fax
http://www.allsystems.com
email@hidden
_____________________________
On 19 Dec 2000, at 11:45, Andy wrote:
>
I have a pre-press production guy asking me to expose all my digital
>
images using a Macbeth chart and adjusting my exposure so that the 3rd
>
gray patch reads 113. He tells me that this allows his color guys to
>
correct color without actually looking at the items in the shot. Am I
>
crazy in thinking this is nonsense?