Purple Definition

I'm seeking some knowledge about how Condes treats purple. With digital printing, providing for the common colour-blind eyes at the same time as normal eyes is difficult, and the discussion elsewhere revolves round a CMYK formulation based on magenta with a percentage of cyan. All I can find in Condes is a colour picker, and the ability to specify custom colours in RGB. I can't see what the default course colour is.

I'm sure that Condes is based on a lot of experience and thought, I would just like to compare that with other discussion, and my experience with specifying purple symbols directly in OCAD. Excuse me if I have overlooked something in the help or phorum.

Hi Michael

The standard Condes course colour is indeed specified in the RGB (Red-Green-Blue) domain as [R=204,G= 0, B=255]. This corresponds to C=20, M=100 in the CMYK (Cyan-Magenta-Yellow-blacK) color domain, i.e 100% Magenta and 20% Cyan, which is a universally agreed best practice value for the course overprint.

Whenever Condes outputs to a format that supports CMYK, the configured RGB course colour is converted to the corresponding CMYK value. This happens when printing to a PostScript printer, and when exporting to EPS and PDF. When printing to a non-PostScript printer, the RGB value is used, as Windows printer drivers are based on RGB colours.

You should be able to see the Condes standard colour value by resetting the colour to the Condes standard value, and then clicking the select colour button to open the colour picker. The value shown in the colour picker should be the configured value.

There is an item on the wish list for new features that it should be possible to configure the course colour as a CMYK value. This means adapting the existing colour picker to support entering a CMYK set of values. This item is fairly high in priority rank.

I hope this addresses your question.

Regards,
Finn



Edited 1 time(s). Last edit at 12/07/2016 03:19PM by finn.

Hi

On the screen, CONDES shows transparent purple, with background colours merging with the purple, like it should be.

When I print a PDF file, the purple becomes solid. I try changing the canvas...map...overprint settings, but all that changes is that the purple become solid on screen when I remove the overprint.

Can you tell me how I get transparent purple.

Thanks

LC

Hi,

When you use the PDF export function in Condes, there is a setting in the PDF export dialog that lets you choose between Blendmode DARKEN and "overprint operator" for overprint effect. The default setting is the so-called Blendmode DARKEN.

The visual result (on the screen and on the printer) is virtually identical for either of these two options.

However, when opening the PDF file in Adobe Reader (and some other PDF viewer applications), the overprint is not shown - colours become solid - when "overprint operator" is used. Adobe Reader has a setting that enables "Use overprint preview". When this setting is enabled, Adobe Reader shows the overprint correctly.

When the file is created with "blendmode DARKEN", there is no need to enable any settings in Adobe Reader - the overprint effect is readily shown without changing any settings.

My recommendation is to create the PDF file with "blendmode DARKEN".

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A few words about using the PDF export function vs. using a PDF printer driver to create PDF files. The PDF export function ensures correct overprint effect and keeps map colours in the original CMYK colour space, whereas some PDF printer drivers create bitmap graphics and uses RGB colours. Using vector graphics ensures the that the image is scalable without loss of quality.
Also, when using a PDF printer driver, even when the PDF printer driver is capable of creating a PDF file with vector graphics, it may not be able to handle overprint effect. If it is, it will use the "overprint operator", forcing you to change the "overprint preview" setting in Adoble Reader, to see the overprint.

If your original map file is a bitmap file, a PDF printer driver may reduce the resolution of the map, resulting in blurred lines. The PDF export function keeps the bitmap file at the original resolution.

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I hope this clarifies. You are always welcome to contact me in this forum or via e-mail if you have further questions or feedback.

Regards,
Finn



Edited 1 time(s). Last edit at 03/17/2018 11:45AM by finn.