[argyllcms] Re: Profiling flexo presses

> No bump or transfer function curve anywhere. Imagesetter output is just well
> linearized and transfer to plate is constant -- no one looses that critical
> 2% dot up to the press. And the press holds it easily. That dot gains like
> hell (2% to 18% on some systems) mind you, depending on the aniloxes used.
>
> >The digital screened file does not have
> > 2% there, for sure.
> 
> Of course it does, Roberto! How else would you transfer a 2% dot on film to
> plates to press?
> 

we're just looking at the problem from different perspective. If your
2% dot grows to 18%, it's no longer 2%. When I talk about printing a
2% dot, I don't mean a 2% file dot or a 2% film dot or a 2% plate dot.
I mean a 2% printed dot, for which you need to output something like
0.2% on film.
You take a linear scale 1%,2%,3%,4%,5% ; image it linear, make flexo
plates and print. Then measure that printout. You measure the 1% patch
and it comes out 10%. Then, are you printing 2%??
If your profiling target has 2% and you don't use a bump curve that
linearizes the *printed* highlights, you will have values starting at
15% or so; basically you'll be using your profile as a rudimentary
linearization, which is not its function.

You might find the following interesting: gives some overview (in form
of product pitch) of many of the color problems inherent in flexo:
http://www.esko-graphics.com/product.asp?id=108

-- Roberto Michelena
   Infinitek
   Lima, Peru

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