I need to use Rhino to get vector 2D draweing into Photoshop, as I used to do from Macromedia Freehand, back the I used export as eps. cmyk option.
There is no eps option in Rhino. instead I choose *.ai (adobe illustrator)
Q1. what is best way of coloring in a closed shape in Rhino before importing into photoshop ?
exporting as cmyk works, rgb sees parsing fail in Pshop.
however… Q2. rhino layers colours are rgb, how do I make cmyk colours for my lines and surfaces.
Its far easier filling colors in , in rhino, than magic wand etc in pshop !
size of a 100mm wide test square opens as 100.19mm thats not very good !
There is a slight gap beyond the 100mm square, but why ? I seem to remember eps was accurate.
No doubt the square itelf is 100mm but why the small margin ?
Method used is select the objects, then export selected as ai,
options . preserve model scale 1mm = 1mm cmyk
Q3 **How do I resolve that small issue, though its not a killer **
Q4. Text in rhino, pshop doesnt recognise parts of it, need to convert to path, what quick way is there of converting my EXISTING text into path retaining its colour fill etc ?
RGB hasnt same gamut as cmyk, so creating my colour fills as rgb then converting to cmyk upon opening in pshop wont give me the correct cmyk.
I am doing aircraft profiles, so normally in Macromedia Freehand or Illustrator one would create cmyk fills, then export as eps and open in Pshop as cmyk, colours then accurate as in compatible/good for commercial print. To have to use magic wand and try to fill areas of colour is a pain, trying to get the ‘crawling ants’ along the middle of a vector line for neatness.
Alternatively to try and drag colour sliders to and fro and create the cmyk mix from the rgb, pipetting it until the cmyk values are what one needs is a total nightmare., impractical in fact.
My only other choice would be to make the export black, turn it into a channel when opened into pshop, then dump a cmyk mix into the selection on screen, but the original in black with black panel lines wouldnt be easy to work on !
I would hope Rhino has a cmyk colour option for when things get printed with ink.
If the colour areas are all separated by vector lines in black; or another color.
The route I would try to take is export the colour panals without the vectorlines*, next export the vector lines as a separate file; either as a vector to be rastered in Photoshop or if need be as rastered black lines against a withe background.
In Photoshop you can adjust the initial rgb colors to the desired cmyk setup. The lines can be superimposed as a layer on top. If need be with a darken only blend is you use the black and white option.
or a colour version with vector lines yet be lenient with the colour selection to let the colours bleed over the vector line.
pdf supports cmyk
I will need Rhino to create the cmyk fills (hatch)
Its not practical though to turn rgb into cmyk.
I will need to make the cmyk in Rhino first. There is no rgb value matches cmyk chart.
I know the cmyk values I need for the various colours, but need to create them from scratch, not try and edit rgb into cmyk.
I always bring panel lines, rivets etc in separately.
so for RAF I import dk green wavy camo then dk earth which is entire aircraft then sky undersides and spinner then panel lines then gap lines then glazing etc…
lay panels over dk green over dk earth etc.
So how does one make the hatches in cmyk in rhino ?
I think your quest is not one that can be fulfilled.
All color in rhino is rgb based, as it is in about every other software not explicitly intended for artwork to be (offset)printed on paper.
It’s very likely you need to do the conversion in the dtp software.
Did you consult those responsible for the printing already? They will likely be able to give advice on how to handle rgb input for conversion to cmyk.
They might even be able to create a conversion profile for you. Especially because no 2 printing setups are the same so they will need to adjust anyway.
Furthermore, I suspect the colors you need, are not even primarily defined in cmyk but in a sytem like RAL or even less standardised. So with all respect, it could be you are on a wild goose chase.
I have a thick tome of cmyk colour swatches, in 5% increments, I select the mix that best replicates the camouflage colour of the aircraft I am doing, then normally set that mix up in Macromedia Freehand as a fill for the camouflage area e.g. dk green.
export as eps and in Pshop it imports as that mix, and Pshop set to Fogra39 current european standard that should match the book when printed.
With no ability then to choose a cmyk mix in Rhino, although Rhino has a cmyk export option, and without that Pshop throws a wobbly saying unable to parse., I guess I will have to create an rgb mix for visual effect only, then at the moment of export, convert the layer to black, export, open as black, make into a channel, blur edges of the channel if need be for sprayed edge camo, then fill the selection the channel makes with my cmyk mix. then revert rhino layer , edit undo.
I shall explore the option of a known rgb value converting to my exact cmyk mix but doubt its possible. Maybe I could try the mix in pshop then con to rgb, set that mix up in Rhino then con back to cmyk in pshop, see if it works.
Since you are manually trying to match a color to a swatch, I doubt that the result will be identical to the original anyway, but…
CMYK to RGB conversion formula
The R,G,B values are given in the range of 0…255.
The red (R) color is calculated from the cyan (C) and black (K) colors: R = 255 × (1-C) × (1-K)
The green color (G) is calculated from the magenta (M) and black (K) colors: G = 255 × (1-M) × (1-K)
The blue color (B) is calculated from the yellow (Y) and black (K) colors: B = 255 × (1-Y) × (1-K)
source: CMYK to RGB conversion | color conversion
Seems like @pascal wrote a script a while ago as well…
It looks to me like two different issues are mixed together in this thread. One is converting between RGB and CMYK values, which is straightforward as described in the link above and the previous post. This assumes the colors are not also being remapped at the same time to deal with different color gamuts.
However Steve appears to also want to remap to a different gamut when the conversion is done; one gamut which he associates with RGB values, and the other gamut which he associates with CMYK values. So what may be needed is an efficient process to do the gamut remapping. Is that possible in Photoshop?