lgm talk, part 1...

[peter sikking]

more gluing:

Chris Mohler wrote:

>> I am curious why you want to do something like that, because you
>> are then going against the grain of the whole plan: freedom to  
>> develop
>> the artistic concept further without (much) rework on the plates.
>
> Imagine I'm designing a black t-shirt with say five spot colors,
> including white.  After completing the artistic design, I enable the
> 'projection screen'.  This theoretically would result in my five
> "plates".  However, the white plate will need special attention.
>
> Here's my workflow for this in PS: I would use the (badly named)
> 'Apply Image' command to take the contents of each color plate and
> combine them into the white plate using the mode 'multiply'.

this looks analogue to me to black generation in cmyk, but now
inverted because we are on a black background. interesting concept,
the media color (makes note). since it is going to work for black,
it can be made to wok for any other color, with reversed logic also.

>  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.

> Now, I am quite interested in learning new workflows - so I am not
> bound to the "how" of the method above, but I hope I have explained
> the "why" well enough.  In addition to being able to interact with
> each plate as a grayscale drawable, it would be useful to create
> temporary areas for doing work - be they layers, channels, plates,
> whatever - on which to create paths, selections, etc to in turn use to
> modify the plates manually.

everything of that will work on plates like working on layers today.
I am sure that global concepts like paths and selection will be
applicable to layers and plates without limits. a selection created
on a layer and applied to a plate: sure.

>  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.

>  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.

> After re-reading the notes on the talk, if we have a Layer->Plate
> mapping, I think that will cover most situations.  I would prefer a
> way to "mix" the plates,

"mixing" channels + layers -> plates is a starting point for the
development of the design of the plate set-up.

> 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?

     --ps

         founder + principal interaction architect
             man + machine interface works

         http://mmiworks.net/blog : on interaction architecture



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[peter sikking]

last one:

(peter) yahvuu wrote:

>>> there's one thing i don't understand, may be a misconception:
>>> why is it necessary to have separate modes for editing the RGB data
>>> and the plates?
>>
>> mainly because creating art on a RGB monitor, to be used on
>> many media, is not the same _activity_ as bringing this art to
>> _one_ particular printing press.
>>
>> also, it is better when the art itself is separated from the  
>> adaptation of
>> it for one press run.
>
> ah, that helps. So it is deprecated to create single-ink 'light blue  
> text'
> directly on  the 'light blue' plate, as the text would then not be  
> known to
> be part of the artwork.

yes, but then I would not stop anybody from doing that. sometimes it  
will
be necessary like applying a ghost image in matte varnish on top
of a glossy full color image: it may be most efficient to do the
matte varnish plate from scratch by itself...

> Can you give an outline how the print color for that text will be  
> specified?

specify a color (pantone, RAL, etc.) for the plate.

> The RGB color isn't useful here and the text layer can't be accessed  
> while
> the press projection is pulled over, IIUC. So each artwork layer  
> will have
> a custom color separation setting resp. color mapping?

no the other way around, each plate gets "mixed" from channels + layers.
I know this is not simple nor solved at the moment. since the plate
is a momochrome drawable, we need to look at the text layer and  
determine
per pixel "how much is there", where 'how much' can be a choice or
combination of the (inverse of) value/lightness/alpha/layer opacity,
and perhaps more.

>>> Is it correct that there's no 'live preview' of the effects that RGB
>>> manipulations have on the plates?
>>
>> if that is really needed by some users (see the two activities above
>> and also "no substitute for experience") then a second view of the
>> file (View->New view) can be run with the projection pulled down.
>> might be hard on the processor.
>
> Regarding the use-case of matching one color from a photo with a
> predetermined ink combination, i think this will be useful.

reading this again I am getting confused what you really mean here.

> yep, that's the desired effect here. For the single-ink text  
> example, a bit more
> than filling the light blue plate to 100% is required, though, as  
> the other
> plates have to be set to 0% for that area.

yeah, I realised that. must be part of the set-up to do that.

> My question is how and where such a layer->plate mapping will be  
> specified,
> for example when i want my text to be (0, 0, 50%, 50% ,0) on the  
> five plates.

well, plates 3 and 4 need to be set up (in the projection set-up) to  
take

0.5 * "the (inverse of) value/lightness/alpha/layer opacity"

     --ps

         founder + principal interaction architect
             man + machine interface works

         http://mmiworks.net/blog : on interaction architecture



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[Chris Mohler]

On Sun, Jun 21, 2009 at 11:22 AM, peter sikking<peter@...> wrote:

>> Imagine I'm designing a black t-shirt with say five spot colors,
>> including white.  After completing the artistic design, I enable the
>> 'projection screen'.  This theoretically would result in my five
>> "plates".  However, the white plate will need special attention.
>>
>> Here's my workflow for this in PS: I would use the (badly named)
>> 'Apply Image' command to take the contents of each color plate and
>> combine them into the white plate using the mode 'multiply'.
>
> this looks analogue to me to black generation in cmyk, but now
> inverted because we are on a black background. interesting concept,
> the media color (makes note). since it is going to work for black,
> it can be made to wok for any other color, with reversed logic also.

Yes, I think media color should be taken into account when designing
this system - even though I suspect the vast majority of media will be
white or very light.

>>  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.

>> Now, I am quite interested in learning new workflows - so I am not
>> bound to the "how" of the method above, but I hope I have explained
>> the "why" well enough.  In addition to being able to interact with
>> each plate as a grayscale drawable, it would be useful to create
>> temporary areas for doing work - be they layers, channels, plates,
>> whatever - on which to create paths, selections, etc to in turn use to
>> modify the plates manually.
>
> everything of that will work on plates like working on layers today.
> I am sure that global concepts like paths and selection will be
> applicable to layers and plates without limits. a selection created
> on a layer and applied to a plate: sure.

OK - thanks for clarifying.

>>  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.

While I doubt that function is necessary, it would certainly be very
useful on occasion.

>>  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.


>> After re-reading the notes on the talk, if we have a Layer->Plate
>> mapping, I think that will cover most situations.  I would prefer a
>> way to "mix" the plates,
>
> "mixing" channels + layers -> plates is a starting point for the
> development of the design of the plate set-up.

OK - thanks.

>> 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:

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).

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

I'd like to thank everyone for participating in this discussion!  I
like the direction that this is headed...
Chris
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[Graeme Gill]

peter sikking wrote:
> 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.

Note that "trapping" has two meanings in the printing world.

One relates to the way the inks stick to what it's being printed
over :- ie. if one plate printed on paper achieves 100% trap (coverage),
then when it's printed on top of a previous plate it might
have 90% trap because it doesn't stick as well to ink as paper, etc.

The other relates to "choke and spread", used to create
plate alignment (registration) tolerance.

Graeme Gill.
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[peter sikking]

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  
micrometers,
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?

     --ps

         founder + principal interaction architect
             man + machine interface works

         http://mmiworks.net/blog : on interaction architecture



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