RGB to CIE-L*a*b*

[protone]

OK, quick background story here and then as much input as possible would be great!! You know how you guys/gals design using RGB, HSB or CMYK colour profiles, and then send those off to the printer to pre-flight and RIP, and then plate and print. Well we get called all the time regarding the needs of supplying the spot colours as we are an ink maker and more times than not generally the proof produced along with the print when the press approval happens, well doesn't always match quite right. Why? 'cause it is designed in RBG/CMYK format and variables as whiteness of paper become a factor, lets face it, ever looked at 4 Pantone books, same colour number, same book format and noticed they all look different? It happens, so here is my actual question--->

Has anyone developed an accurate colour management system through design to press to print where proofs very accurately match print output (press), ink makers work in *L*a*b colour format where printers and designers work in RGB/CMYK so at times we talk a little different in the precise values of colour. Has anyone ever co-ordinated the RGB to L*a*b conversion for an ink maker or even vice a versa L*a*b to RGB? We use software to convert for the Printers when asked but I would like to develop a better system for matching designer needs to client acceptance which include Printer and ink maker.

Does design software provide *L*a*b colour spectrums or is it only RGB/HSB/CMYK? Curious to know how you all deal with it?:o

[prepress_goddess]

Photoshop does have a L*a*b color mode, but I have not run into any color issues in dealing with my ink suppliers. we run strictly CMYK or Spot Color via the Pantone Book. Any color issues I have dealt with have been with customer color percecption when dealing with the final printed piece on the chosen stock.

[panzer]

seems more like a question you should be askinf fellow ink makers m8

[PrintDriver]

Broacher, I'm sure, will have something to contribute re lab colors. Seems I remember him prefering to work with them in some instances.

So press people have trouble with color too, even with all the Solid to Process and Bridge guides. LOL. I thought it was just us digital geeks.

I've often wondered about signing off on digital proofs when getting a press run done. There are many colors that are simply out of gamut in a digital print process that can be printed with spot color on press. I dont' know if there is any color management system that can help with gamut issues. Careful profiling of materials for both systems may help but...

[prepress_goddess]

The last shop I worked at used the Best Color RIP for proofing color and it actually used the L*a*b conversion. Was a little tricky getting used to but it did an awesome job - the presses were fingerprinted and the curves loaded into the RIP. Using the ICC profiles for the material to be printed made the proofs almost identical to the press sheets. It was REALLY accurate with the pantone color matching as well - outputting to an Epson 7600