From: Jack Fulton (jefulton1@attbi.com)
Date: 02/09/03-10:42:29 PM Z
Alan et al:
This depends upon your camera and what it rendered. I am speaking of
digital cameras. There is an 'action' in Photoshop which converts color
images (scanned or digital) to grayscale. It averages portions of each
channel and seems to be mighty smart in doing so. Try it. You will like it.
Jack
> I have heard from a few sources that using the green channel in an RGB
> scan will result in the most accurate conversion of tonal values.
>
> any other thoughts?
>
> -Alan Bucknam
>
>
> On Sunday, February 9, 2003, at 12:03 PM, jacques verschuren wrote:
>
>>
>> I converted a grayscale stepwedge to RGB and noticed that a change in
>> density occurred:
>> Grayscale 0% changed to 0% RGB, 5% to 4%, 10% to 8%, 20% to 16%, 30%
>> to 24%, 40% to 33%, 50 - 42, 60 - 52, 70-62, 80-72, 90-84, 95-90,
>> 100-100. Converting back to grayscale resulted in the changed values
>> in grayscale. In order to calibrate and apply curves to images is it
>> advisable to print the grayscale image as an RGB file on a desktop
>> printer? Or convert grayscale to RGB and than re adjust the changed
>> values to the original?
>>
>> Jacques Verschuren
>
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