Re: Who Does the Separations?
Re: Who Does the Separations?
- Subject: Re: Who Does the Separations?
- From: "Robert J. Hennessey" <email@hidden>
- Date: Thu, 04 Jan 2007 17:43:07 -0500
- Thread-topic: Who Does the Separations?
Title: Re: Who Does the Separations?
Hello Karl,
It has not been my experience when making edits in CMYK that they are in any way “unpredictable.” As I stated in my original posting, I make different edits in RGB, LAB and finally CMYK. Control is the key to achieving a predictable result. I, too, use color management as a tool for consistency and predictability. As I make separations that print all over the world, my preparation is specific to the printer I’m collaborating with for each project.
I, myself, am not involved in making separations for all applications and commercial printing processes, but I do know how to prepare separations for almost any ink on paper process. Generally speaking, I agree with your observation that “ the color transform should always be done at the last step.”
I do not agree that “With a good printing profile, that matches the printing conditions,
everybody can perform a perfect separation.” But this is only because I have never actually seen a perfect separation. In my twenty-five plus years of producing illustrated books for museums and book publishers, that has yet to happen.
Best Wishes,
Robert
On 1/4/07 3:01 PM, "email@hidden" <email@hidden> wrote:
>
> Am 04.01.2007 um 15:00 schrieb Robert J. Hennessey:
>> But the essential printing inks are CMYK. This is the final edit
>> space and is useful because each color channel can be adjusted
>> individually without affecting any other channel.
> True, but the results are unpredictable! If you just want to make an
> image darker or lighter in CMYK, you may have to color correct
> certain areas afterwards. Due to an uneven gray balance, the
> "distance" between C,M and Y is different in different lightness
> areas. Thus, when you change lightness by moving all 3 channels up or
> down, you end up somewhere, where gray balance is different and you
> unintentionally introduce a color cast. This will not happen in a
> well behaved RGB working space, where gray is R=B=G.
>> If CMYK is the destination of your image, then it will help insure
>> your success to be familiar with what the CMYK numbers mean. There
>> are many very good texts to use as a guide.
> Who would be familiar with all flavours of CMYK (newsprint, gravure,
> flexo ...)? Since CMYK is not equal to CMYK, the separation (or color
> transform) into a printing space (be it CMYK or RGB) should always be
> done as the last step. Otherwise you end up converting from one CMYK
> to another and a third ..., losing quality along the way in each one
> of the conversions.
> CYMK values are unsuitable to describe COLOR, CMYK just describes
> percentages of ink on paper (or film, or plates), without saying,
> what the ink looks like.
>
> With a good printing profile, that matches the printing conditions,
> everybody can perform a perfect separation. That means, the
> separation needs to be done, when the printing conditions are known,
> i.e. at the printers.
>
>
> Best regards,
>
> Karl Koch
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Colorsync-users mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden