bossanova808
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« on: July 08, 2010, 02:03:56 AM » |
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I've been corresponding with Mike but I thought I'd also discuss this here to see if anyone else is having similar problems. We are a print service provider doing maybe 50 to 100 prints a day from client prepared files, so our needs are different to many of you. Now, Mike has said PSD is proprietary and the size tags are an issue (although I do find myself wondering as I know of no other image program that can't read these tags pretty easily, and we use a LOT of them here - there are a number of PSD codecs that could be used I believe which might be a way forward for Qimage?). Anyway, we don't get many PSDs so we can live with this by converting them to TIF, but we're having issues with JPG sizes as well. We're finding that when QImage is set to Custom->'Orginal size', the overrride switch is NOT set, the crop thing (scissors) is turned OFF, that when we place JPGs some of them come in at the wrong size even so. We notice it with 360PPI JPGS - it's as if QImage is behaving as if the override is set to 300, as Qimage renders the size to the 300PPI size (that is, bigger than they should be). Has anyone else run into this, or do you ahve any ideas why this might be occuring? It's 100% reproduceable. Here's two JPGs which should print at the same size but don't - http://dl.dropbox.com/u/108804/JPG%20Size%20Problems.zip |
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rayw
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« Reply #1 on: July 08, 2010, 02:46:16 AM » |
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The images you sent are different sizes - Irfan view, for example gives the image properties as 2100 x 2672 and 2520 x 3206 pixels. The X/Yresolution is part of the exif tag, and I guess Qimage (and other software) ignores that. That makes sense to me, since the dpi will be meaningless if you print in different sizes, and it sets the print dpi to match the printer _but_ Qimage does show 300dpi for both images on the bottom line (what it would show if you could set the x resolution to be different than the y in the exif, I've no idea). Qimage has the max. printer resolution set to 360dpi for me.
I guess you'll have to do some sums to get the size you want, if you only have the dpi and pixels to work on.
Best wishes,
Ray
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bossanova808
Newbie
Posts: 8
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« Reply #2 on: July 08, 2010, 03:03:22 AM » |
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You're misunderstanding - in 'Original Size' mode, the tagged PPI is supposed to be respected - that's the point of that mode.
Both images are tagged with the same physical size, but they have a different PPI (300 vs 360).
The fact QImage is not reading those PPI tags is precisely the problem - they are NOT both 300 PPI and are correctly tagged as far as I can see...so when using Original Size printing (which we need to do as clients supply us sized files) - these will print incorrectly.
(I fully understand the whole let Qimage do the interp. thing etc, but this is a different point - when in original size mode, it should read the tags and print at that size!)
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rayw
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« Reply #3 on: July 08, 2010, 03:19:26 AM » |
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open the images in Irfan view or similar - the image size tags are blank (but the exif ones are set.)
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bossanova808
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Posts: 8
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« Reply #4 on: July 08, 2010, 03:44:38 AM » |
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ah ok, that's really interesting - Photoshop shows a size for the images (one 300, one 360). So maybe Photoshop isn't setting these tags right when it saves the jpg.
Grrr - hmm, EVERYONE uses PS to save the JPGs - well, for us, literally thousands of clients. That's a bugger.
Ok - I guess some sort of script to convert the files and set the EXIF tag to the normal tag (JPG header tag I guess?). Hmm, might be easiest just to write an acton/droplet that converts everything to TIFF.
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BrianPrice
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« Reply #5 on: July 08, 2010, 06:58:46 AM » |
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Hi I tried out your files and as you say the problem is re-producible. Ray has got it right, the exif data has been stripped after the files have been saved in Photoshop. Opening and closing the files in PS results in QI reading the size correctly, But I ran the saved files through an exif stripping program ( http://www.download3k.com/Install-Exif-Tag-Remover.html ) and the original problem returned. Some photographers strip exif from all their shots for various reasons although I've never understood it myself, or they may be using some program other than PS. This definitely seems to be a weakness in QI which Mike may not have come across before, but he is very good at sorting these things out quickly. In the meantime you may be able to narrow it down to certain clients and run just their files through PS in a droplet. Brian |
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bossanova808
Newbie
Posts: 8
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« Reply #6 on: July 08, 2010, 07:11:04 AM » |
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Yep we've already made a droplet and it's just converting all PSDs, JPGs etc to TIFFs - we've not see the problem with TIFFs so presumably it's something to do with CS5 not writing the size tag (Well, PPI) to the JPG Header. And PSDs being proprietary.
That 'solves' it for now, but it's definitely cumbersome. It would be great if QImage could check the EXIF is the JPG header ones aren't set.
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BrianPrice
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« Reply #7 on: July 08, 2010, 08:53:38 AM » |
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Hi Opening in Photoshop and saving as Jpeg solves the problem in the same way as saving as Tif - could save you disc space  Brian |
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bossanova808
Newbie
Posts: 8
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« Reply #8 on: July 08, 2010, 09:29:01 AM » |
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Hmm, I tried that in PS CS5 Extended and it just re-saved the file without tags again. I wonder if there is a setting hidden somewhere to do with this???
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Fred A
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« Reply #9 on: July 08, 2010, 09:53:44 AM » |
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I must be missing something!!
I got the two images. They have different resolutions. Original size places them both in the queue at the same print size (7.00 x 8.91) with one at 300 ppi (the lower resolution) and one at 360 ppi (the higher resolution)
are you saying that you get them both at 300 ppi?
Fred
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Fred A
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« Reply #10 on: July 08, 2010, 09:55:31 AM » |
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Also wanted to mention that PSD files do not carry the embedded ppi when you save them.
Fred
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bossanova808
Newbie
Posts: 8
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« Reply #11 on: July 08, 2010, 10:10:10 AM » |
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Ok that's VERY interesting - I am indeed saying they go into the queue as different physical print sizes (both go in as 300DPI). Why would it be different for you than us - with those two exact files??
What version are you using, and can you confirm original size, no override PPI, no cropping etc?
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Fred A
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« Reply #12 on: July 08, 2010, 10:40:54 AM » |
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What version are you using, and can you confirm original size, That's an oops! on my part! I apologize! The 300 reads, but the 360 reads as 305. I typed in the 360 and checked it. Fred |
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admin
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« Reply #13 on: July 08, 2010, 12:58:53 PM » |
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For whatever reason, Adobe has decided to omit the JPEG (JFIF) file header in CS5 so there is no embedded resolution/size any more in the JPEG file. As noted, there is a resolution embedded via the EXIF header inside the JPEG but IMO, that's not where it belongs since: (a) EXIF data is optional and (b) cameras are the only devices that add EXIF info and they have no business deciding resolution. Logically, removing the resolution from the JPEG header doesn't make much sense but by the specs, there's not anything technically wrong with that so I can fix it in a future version by dropping back to the EXIF resolution tag when the JFIF header in the JPEG is missing. For now, I'd just use TIFF if you can. Leave it to Adobe to find non-standard ways of using a standard.  Mike |
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Ernst Dinkla
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« Reply #14 on: July 08, 2010, 01:14:32 PM » |
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For whatever reason, Adobe has decided to omit the JPEG (JFIF) file header in CS5 so there is no embedded resolution/size any more in the JPEG file. As noted, there is a resolution embedded via the EXIF header inside the JPEG but IMO, that's not where it belongs since: (a) EXIF data is optional and (b) cameras are the only devices that add EXIF info and they have no business deciding resolution. Logically, removing the resolution from the JPEG header doesn't make much sense but by the specs, there's not anything technically wrong with that so I can fix it in a future version by dropping back to the EXIF resolution tag when the JFIF header in the JPEG is missing. For now, I'd just use TIFF if you can. Leave it to Adobe to find non-standard ways of using a standard. Mike Mike, Good to know that. Not at CS5 yet though. How will CS5 recognise the size of a CS5 exported JPEG? met vriendelijke groeten, Ernst Dinkla Try: http://groups.yahoo.com/group/Wide_Inkjet_Printers/ |
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