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Halftone and Color Separations
Hello.
I'm working on a silkscreen project and need some halftone gradients, preferrably auto generated if it's in Xara...
Is this feature somewhere to be found in export? I'm not sure exactly where to look. I'm fine with registration marks and such, I just put on my own for reference, but I'm not sure how to go about 'faking' halftone patterns if I have to do that, assuming the likelihood of halftone exports not being in Xara. I'm using 15/X btw.
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Re: Halftone and Color Separations
there is no halftone export in xara
as for 'faking it' - here are a few threads I googled:
https://www.google.com/search?client...+halftone#ip=1
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3 Attachment(s)
Re: Halftone and Color Separations
No idea if this is of any use.
I just built it: Attachment 134138
Ctrl-click on the image and Replace Photo.
Whatever you do, the image must keep the Image Filename photo.
I cannot recall if this exists in XDPXv15. Do ask if it isn't, there is a workaround.
A mouse-over shows the original.
Xara has yet to fix when an image changes, the Image Filename gets suffixed.
You have to Preview a second time!
In Website Head, most of the variable to tweak things are under :root.
My test piece:
Attachment 134140
Original:
Attachment 134141
Acorn
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1 Attachment(s)
Re: Halftone and Color Separations
First: this photo will not drag and drop into DPro+. Once I do manage to get it into DPro+ it locks up the program and I have to restart Windows to get the program to close.
Second: this is a halftone effect and not a halftone.
The difference is a halftone only contains solid black over white. The size of the individual black halftone dots become larger or smaller to represent the in between tones.
https://en.wikipedia.org/wiki/Halftone
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Re: Halftone and Color Separations
takes me back to letratone....
and ben day, although that is dotty in a different way :nerd:
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2 Attachment(s)
Re: Halftone and Color Separations
Quote:
Originally Posted by
gwpriester
First: this photo will not drag and drop into DPro+. Once I do manage to get it into DPro+ it locks up the program and I have to restart Windows to get the program to close.
I distinctly said Replace Photo. The image is soft-grouped so dragging may not work and you probably will have lose the Image Filename.
I have just tried Ctrl+Select the current image and then dragging the new image onto it with no issue. Repeated several times (XPro+).
Quote:
Originally Posted by
gwpriester
Second: this is a halftone
effect and not a
halftone.
The difference is a halftone only contains solid black over white. The size of the individual black halftone dots become larger or smaller to represent the in between tones.
https://en.wikipedia.org/wiki/Halftone
To get pure black dots, you just ramp up the Line Contrast:
:root {
--dot-size: 0.25em;
--line-color: #000;
--line-contrast: 2000%;
--photo-brightness: 80%;
--photo-contrast: 150%;
--photo-blur: 2px;
--blend-mode: hard-light;
}
The same WP article also covers the dot shape, round, elliptical and square.
The parameters chosen can be adjusted for these.
Attachment 134143 500% zoom on original with above settings.
Attachment 134144
Yet to try colour separation. Up to now I have used ImageJ2, which is a massively powerful tool.
Who knows? Xara might have a few tricks lying around.
Acorn
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Re: Halftone and Color Separations
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Re: Halftone and Color Separations
@acorn
interesting - how do I export the halftone as an image file ?
I tried both export website look in folder, and screen save from browser - neither worked, though I may be doing something wrong, not being a web-doc guy... thanks
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Re: Halftone and Color Separations
Quote:
Originally Posted by
handrawn
@acorn
interesting - how do I export the halftone as an image file ?
I tried both export website look in folder, and screen save from browser - neither worked, though I may be doing something wrong, not being a web-doc guy... thanks
handrawn, Xara has still failed to handle post-processed images. I revert to A3 Landscape PDF printing from the browser or a screenshot.
Acorn
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Re: Halftone and Color Separations
if I print to PDF I get greyscale, not halftone - but based on what you have previously said, am I right in thinking this does not work in firefox?
if so, can I view it from xara in another browser without changing my windows default,which is not an option at the moment...
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1 Attachment(s)
Re: Halftone and Color Separations
This is one of those long-forgotten features that has been a part of Xara since day one almost. And to the best of my knowledge has never been touched or updated.
I have never used it because it is really the print company's job to do the color separations but it's all there plus 9 different screen/dot options. And a full range of printers registration and other marks.
It's in Print > Options
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Re: Halftone and Color Separations
Gary - as I recall those separation and screen/dot options are for printing directly to a postscript printer; I'd forgotten the dot options, still not having a postscript printer cannot check...
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Re: Halftone and Color Separations
Quote:
Originally Posted by
handrawn
if I print to PDF I get greyscale, not halftone - but based on what you have previously said, am I right in thinking this does not work in firefox?
if so, can I view it from xara in another browser without changing my windows default,which is not an option at the moment...
You have to twiddle with the :root values.
Up the --line-contrast to a very large value. Increase the --photo-blur to recover the roundness of your 'dots'.
Possibly, also increase the --dot-size. Change --blend-mode to screen.
Use the highest rendered size as the monitor will be showing 96dpi.
Remove Xara dithering.
The rest depends on the image.
You could set its Contone Dark to Black. You could tweak the Transparency settings.
The alternative is to screenshot, paste back into Xara or a bitmap editor and manipulate with the Photo Tool.
I have even brought the screen shot back in as the source image.
As it does not work in FF, copy the URL and paste into another browser.
I refer my learned friend to my opening statement, "No idea if this is of any use."
Acorn
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Re: Halftone and Color Separations
Quote:
Originally Posted by
handrawn
Gary - as I recall those separation and screen/dot options are for printing directly to a postscript printer; I'd forgotten the dot options, still not having a postscript printer cannot check...
@handrawn, the bottom block is for colour separation for any printer. If you choose PDF export then you get four registration plates in the document. These are all greyscale so I do not think they help.
Acorn
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Re: Halftone and Color Separations
Quote:
I refer my learned friend to my opening statement, "No idea if this is of any use."
I was interested in how practical it might be... not very it seems if you already have [for example] cartoon software that will export in halftone the way I believe the OP was hoping xara would - but an interesting aside...
it does work as far as I can see in edge...
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Re: Halftone and Color Separations
... oh any ide what the screen/dot options are there for, I can't see they make any difference to the separations....
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Re: Halftone and Color Separations
Quote:
Originally Posted by
handrawn
... oh any ide what the screen/dot options are there for, I can't see they make any difference to the separations....
No, 'cos those are for PS printers.
I do note that Xara's 'Help' on this is misdirected; a common failing!
Just in!
Quote:
Screen/dot type: PostScript printers can print halftone dots in a variety of shapes. Generally round dots give the best results but some presses work better with a different dot shape.
Acorn
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Re: Halftone and Color Separations
Quote:
No, 'cos those are for PS printers
indeed... as I thought, thanks
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Re: Halftone and Color Separations
Theoretically this could be used to generate a PostScript file that a printing company could RIP to create 4-color separations for commercial printing. But these days it is easier to create a PDF/X file and let the printing company do the rest.
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1 Attachment(s)
Re: Halftone and Color Separations
Playing around further, I've found if you make the --photo-blur -1px (yes, negative) and also adjust the --dot-size to zero or close and tweak the --line-colour, you can get some powerful posterisation effects.
Attachment 134147
came about with these :root settings:
--dot-size: 0.5em;
--line-color: #8b3f1a;
--line-contrast: 185%;
--photo-brightness: 80%;
--photo-contrast: 250%;
--photo-blur: -1px;
--blend-mode: hard-light;
To do your own interactive tweaks open the browser elements for the page and expand the <head> and the last <style> entry to reveal the :root settings in the Styles window.
You can select most values with numbers and when highlighted, use the Up/Down arrows to increment/decrement.
Acorn
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Re: Halftone and Color Separations
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Re: Halftone and Color Separations
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Re: Halftone and Color Separations
Quote:
Originally Posted by
haakoo
Very powerful too.
+1
Acorn
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3 Attachment(s)
Re: Halftone and Color Separations
Quote:
Originally Posted by
haakoo
I like this one. I can see myself whiling away a few enjoyable hours in the near future.
Attachment 134149 Attachment 134150 Attachment 134151
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1 Attachment(s)
Re: Halftone and Color Separations
Quote:
Originally Posted by
Chris M
Here's recorded proof of my early matter transmission experiments:
https://shared.xara.com/tiP5TZdyj3
Attachment 134153 - this requires an XDA that handles SVGs...
Acorn
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1 Attachment(s)
Re: Halftone and Color Separations
When all you have is a halftone, every problem looks like a stereogram.