Chris Mohler wrote:

>>>  I would
>>> also manually "choke" the white plate - this means making the white
>>> areas a point or two smaller than the colored areas, thereby
>>> preventing the white from poking out at the edges of the colored
>>> areas.
>> this looks like trapping to me. is there a difference?
>> trapping set-up for each plate would be in the projection set-up.
> A "choke" is a trap of negative amount.  This is probably just jargon
> -  I suspect that it should in fact be called a negative trap.
> Automatic trapping (and overprinting) has never lived up to my
> expectations - I would love to hear from anyone who has used
> auto-trapping software with acceptable results though.

would you call setting for each plate the amount (in points or  
etc) of choking or trapping to be automatic or manual?

>>>  Icing on the cake would be a mechanism to
>>> combine/subtract plates using the available blending modes.
>> to generate plates from channels/layers that is needed, but
>> generating plates from plates? sounds like a creative kind
>> of workflow to me.
> I remember one specific instance:  printing two blue colors - one
> light, one medium - on very dark blue.  We originally placed the light
> blue color behind the medium blue color (overprint).  The client
> changed their mind,  and I needed to remove the overprint.  Merging
> the (inverted) contents of med blue into the contents of lt blue
> removed the overprint in one step.  I basically masked one plate with
> another and applied the mask.

and now it looks like a plate set-up change

>>>  During
>>> the process, it is fairly critical to have an ink density/opacity
>>> setting for each plate, to simulate (roughly) how the final print is
>>> going to look.  EG, set the white plate at approx 90%, the colors at
>>> approx 70% - and you can see which portions of the colors are  
>>> falling
>>> on the white underlay, and which portions are falling on the black
>>> shirt.
>> hmmm, tricky that one. it is natural for the plate stack to work
>> sort-of like the layer stack. eye symbols to switch plates on/off.
>> then there is the opacity slider of the layer stack. coverage slider
>> for the plates? ay be does the dual purpose of previewing like you
>> need and absolute print balancing.
> Indeed - the stack of plates should function more or less like the
> layer stack.  Yes - I envision a visibility toggle for each layer, and
> also an opacity slider.  But here's another murky area  (as if we
> needed more ;) - if I set a plate's opacity to 50%, does 100% black on
> that plate print out at 50% or 100%?  I would expect 100% - but that's
> from past experience, and not very intuitive.  Perhaps you are right
> that we need both a opacity and coverage control - that makes more
> sense to me,  but I have never seen it implemented and may well prove
> confusing.

no it would have to be a slider with results, so it would really
scale the whole plate coverage. and similar to layer opacity today
you can use it in between to peek though a layer. that should be enough

>>> and to be able to add new layers that could
>>> later be applied to new or existing plates, but this could be worked
>>> around.
>> add layers where, image side or press projection side?
> My guess is image-side.  One possible scenario:

OK, all clear there.

> 1. Design artwork in GIMP - RGB, 3 colors, 1 color per layer - 3
> layers (or maybe 4 with a bg color)
> 2. Create print projection, map layers to plates
> 3. Done, hit print/export - OR
> 4. Go back to RGB, duplicate two layers, merge them, apply curves, etc
> - whatever needs adjustment
> 5. Manually apply the contents of the new layer to one or more of the
> plates in the projection
> 6. Done, print/export
> I guess to summarize: in addition to the initial layer(or color?) ->
> plate mapping, it should be possible to re-apply contents of one or
> more RGB layer to the plates without re-mapping the entire projection
> (if that makes sense).

well, if you want some layers to do something special to some plates
you will have to map them. this does not mean re-doing your mapping,
just updating it a bit.

> Things like overprints and trapping can get very complicated, esp if
> the colors are not solid and/or you are mixing spot colors.  Often
> fine-tuning is required.  I would love to see automatic trapping
> (complicated!), but not without being able to manually tune the
> results

for instance using the (perpetual) upcoming iWarp tool on the plate
would a cool way to do thet, no?


         founder + principal interaction architect
             man + machine interface works
 : on interaction architecture

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