QTR-Quadtone RIP

On Monday, September 4, 2006, at 02:03  PM, Ernst Dinkla wrote:

> Roy Harrington wrote:
>
>>>
>>
>> I think Ernst may have pinpointed the issue.
>
>
> Roy,
>
> I'm not so sure about that right now.  I have done this before
> and I think I made the same mistake again. Qimage actually
> does exactly the same as Photoshop does when CM is off in both
> applications. When CM is off in PS the Greyscale one will
> convert to the same RGB numbers the Qimage conversion makes
> when CM is off. So Qimage and Photoshop behave the same when
> CM is off. The plain TIFF converter of my website that has no
> CM at all produces the same numbers.
>
> When the Qimage Print to File RGB file is brought back into
> Photoshop  and converted to greyscale (with CM on) to compare
> it to the original that was loaded to Qimage then there's a
> difference but that is because the CM in Qimage was off and
> the CM in Photoshop was on. With CM off in Photoshop the
> Qimage produced RGB file will convert back to the same
> greyscale percentages on the steps.
>
> I guess QTR has the same conversion for RGB>Greyscale as
> Qimage and Photoshop have with CM off. In that case my
> workflow with greyscale converted to the QTR grey printer
> profile, then loaded in Qimage with CM off and the print to
> file RGB sent to QTR which converts it back to greyscale is
> still valid and there is no fault in Qimage.
>
> Ernst
>

Photoshop doesn't really have a CM off mode when you do
conversions.   What you have set in Color Settings -- the working
spaces determines what happens.

I'm not sure what Qimage does in these cases.

Roy


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>            Ernst Dinkla
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Roy Harrington
roy@...
Black & White Photo Gallery
http://www.harrington.com