Black looks grey on PDF!

[gdavidson]

Hi!

Gosh... I'm not having much luck In relation to working around a bitmap resolution printing issue, I have been exporting to PDF and printing from Acrobat. On the printed copy I noticed that the border looked grey and the picture had a true black line around it - much blacker than the frame.

Sure enough, when I opened the PDF in Acrobat and looked closely - there it was... a true black outline around the picture and a relatively grey frame.

Xara's colour picker says the grey looking colour is black (0% H S V and every other colour model says black too!)

I have attached a copy of a photo I was working on but have reduced the photo resolution immensely as it was 27Mb!!

If you export the file as PDF you should see the frame is grey and I have made a square behind the white test that says "Black" on the left. I could not make such a black square in the normal way (clicking on black), instead I had to copy the colour with the dropper tool from the black line around the photo!!

I'd be grateful if someone could replicate/verify this for me. One caveat though... if you are using an uncalibrated or standard LCD monitor you *might* not see the differences in the blacks!!


Thanks!

[Charles Moir]

The reason is the two blacks are different blacks. One is a HSV black and one is a CMYK black. Adobe, it seems, deem these two as different. Xara deems them to be the same.

I can understand why they are different. The CMYK black, as defined, will print 100% solid black using the black ink only. RGB and HSV blacks, depending on the exact printer being used, will more often print black with some other inks added, typically cyan. This makes an extra dark black, if you see what I mean. (This is an old printing trick to create really dark blacks that's been used for many decades).

So the simple answer, if you want it all to be the extra black, is to re-define the black border to be RGB black, and to do that, in the colour editor, make sure you're in RGB or HSV mode and make sure the blob is dragged to black.

You can set your colour picker to show CMYK and RGB colours by going into options dialog, View tab, and selecting 'automatic colour model'. That way when you click on colours the editor will show you whether they are CMYK or RGB. (Normally Xara is set to always show colours in the HSV picker, even if they are CMYK colours - because that's easier for most people to understand).

CMYK can be a complex subject, but I hope that helps.

[gdavidson]

Hi Charles,

I'm honoured to have the top man to be looking at the issue - thank you!

I can see that I may have come unstuck when I was looking at the blacks with the colour picker. Each colour model claimed it was black but there seemed to be no way to identify the colour model it was using. However the act of changing to RGB and then moving the colour sliders up and back down to 0 had the effect of making it truly black in the PDF!

Just so that I am clear on what happened there - is it the case that if you start out with one colour model and change to another, that unless you go through the act of modifying the colour and resetting it back via sliders or value entry, it will remain in the original colour model (apparently CMYK in this instance)? That would seem to be what has happened as if I make a black square with CMYK, it appears grey in PDF but if I change to RGB and go through the act of moving the sliders up and back down to 0 it then shows as very black in PDF.

Actually, thinking about it a little more, when I originally chose the frame colour I used the "black" from the colour picker bar at the foot of Xara. When I go to edit the colour "black" it does indeed show up as a CMYK colour with the remaining shades of grey beside it as a tint of black.

Thanks for the information - it has helped greatly and resolved that problem nicely!


P.S. Whilst I have your attention Are you aware of any resolution capping when printing bitmaps from Xara to a high resolution photo printer via a non-PostScript printer? (Exporting to PDF with bitmaps at 600dpi and printing in Acrobat is a workaround)

I'm finding that when I print 10Mpixel photos onto a 6 by 4 sheet directly from Xara there is a notable loss of detail in comparison to other applications printing the very same image at the same size. The printer, an Epson R800, has a scary resolution (5760 dpi x 1440 dpi) and it occurred to me that perhaps Xara was either misreading the printer driver's resolution or not expecting such large figures and capping it at a lower resolution. I could be totally wrong about that

I'd love to be able to print direct from Xara and achieve the same results as the PDF export workaround I am using at the moment

I appreciate your help - Thanks!

[AntonyF]

is it the case that if you start out with one colour model and change to another, that unless you go through the act of modifying the colour and resetting it back via sliders or value entry, it will remain in the original colour model (apparently CMYK in this instance)?

I can say yes to that one. I just put the cursor in one of the numbers and hit enter, that achieves the same result.

[PhilM]

Hi Graeme,

Yes there is resolution control in Xara Xtreme's printing system. The reason for it is to set a resolution when we have to convert some of our more complex rendering into simple bitmap graphics for the printer driver.

I can't see why your example doc would trigger that resolution control but printing is a deep and complex area so you never know.

You can control it yourself from the Print Options dialog: Open Print Options, go to the Output tab, change Bitmap Resolution to "Manual" and then tweak the resolution field to see if that helps with your problem.

Xara Xtreme's printing system is smart about memory usage, it prints in bands whose size depends on the memory available, but nevertheless you might hit problems at very high resolutions.

Hope that helps.

Phil

[gdavidson]

Thanks Antony and Phil!

Phil, the example I posted was actually a *very low* resolution copy to demonstrate the PDF black/grey issue. The actual bitmap is a 10Mpixel image which makes the original .xar file around 16Mb which I thought was rather too large to post

I'm going to play with the bitmap output settings to see what happens. I do recall when I set it to 300, the output came out sharper but rather more pixellated, as if an antialiasing step had been removed (I had likely chosen bitmap and not antialiased bitmap output). I will wind it up to the maximum of 600dpi to see what happens.

Is there any way to go beyond 600 dpi via this method? I have 2Gb of ram in the machine (dual Xeon too).

Thanks for your help!

[PhilM]

I realised that doc was not "the real thing" but what I didn't spot was that you've got it set to "Print As..." "Bitmap".

Have you tried "Print As.." "Normal" and then altering the "Transparency resolution" setting manually? That was what I really meant.

Phil

[gdavidson]

Hi Phil,

Thanks for the info - I'll give that a try too and see what happens!

I didn't realise the print option settings were saved in the document itself - learned something new there!

Thanks!

[gdavidson]

Hi Phil,

Some interesting outcomes for you here! Overall I have had some success and discovered a little anomoly in the process

The test image I used was a 1inch by 2inch crop of the grass, placed in a corner so that I could use a photo sheet 4 times in the testing process. Well - that was the plan!!

If I print the photo with the print options set to "antialiased bitmap" and a resolution of 600 dpi, the quality is good enough for my purposes and comparible to other applications. Surprisingly if the antialiasing is not used, the printer resolution is sufficient to *just* see the aliased edges on long arches of grass stalks. When printed this way, the printer actually prints transparent gloss (it uses a transparent gloss optimiser coat) the whole width of the image in the corner but also to the full height of the sheet, glossing unprinted areas. I think this may be the way the printer sees the bitmap when printed this way. Due to that I couldn't use the paper 4 times; just the twice - you can't reprint on top of gloss.

I then tried setting printing back to "normal" with a transparency resolution of 600dpi and something really good happened. The image came out with the *same* high resolution quality as the other good ones but the printer only applied gloss to the image area - no glossing on the unprinted areas... yipee!

In a nutshell, you can print a good quality bitmap image with the settings at normal if you set the transparency resolution to 600dpi! Just the way you described!! If you print to bitmap, you'll get gloss coat in unexpected areas.

If I set the transparency resolution to Automatic, the printed bitmap resolution takes a big dive, which is what got my attention originally.

I wonder why the transparency resolution should have such an effect on printed bitmaps?

Thanks for the help - I really do appreciate that. For now I seem to have a good workaround - thank you!

I've only got one more stumbling block (oh-no, not another!)!! When working with camera RAW files, the Nikon Capture workflow will result in the production of 16bit tiff files which Xara cannot import correctly. Can you tell me if 16bit tiff is currently not supported in Xara or could it be a weird dialect of tiff that it upsetting Xara?

Thanks!

[Jon G]

I tested and also get issues with importing 16-bit tiffs from Pixmantec RawShooter. 1/4th of the left side of the image has only magenta.

These open without problems in GIMP and Photoshop.

Jon