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How to Increase DPI of Deep Zoom Tools Output Images?
Hi
I am using DeepZoomTools Library.I have created image pyramid in C# like deepzoom composer does ,the problem I am facing is that I want to increase dpi of output images which have been created by deepzoomtool.I have also observed that DeepZoom Composer also produces output images with dpi =95.
But if dpi of input image is >95 i.e 600 deepzoomTools library produces output images with only 95 dpi.We want to maintain dpi of output images as same as source image i.e 600 .Help in this regard would be highly appreciated.
I am using DeepZoomTools Library.I have created image pyramid in C# like deepzoom composer does ,the problem I am facing is that I want to increase dpi of output images which have been created by deepzoomtool.I have also observed that DeepZoom Composer also produces output images with dpi =95.
But if dpi of input image is >95 i.e 600 deepzoomTools library produces output images with only 95 dpi.We want to maintain dpi of output images as same as source image i.e 600 .Help in this regard would be highly appreciated.
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Inappropriate?An image's DPI is only used when printing, which presumably you won't be doing with the individual tiles of a DZI. You haven't lost any pixels; your image still has the same resolution, it's just missing the DPI marker.
Does that answer your question, or do you need the DPI marker for something I haven't thought of? -
Inappropriate?Ian, I'm sure you know what you're talking about but I know I've seen raster images noticeably change scale when running monitors at a higher DPI (back when I used mainly CRTs) and has at times resulted in image pixels being larger than desktop pixels. Perhaps this is because the programs were not properly coded to be resolution independent, but I was wondering how long it had been since you had reason to set your DPI higher than 96 in this era of LCDs and plasma displays who have a locked number of pixels that does not generally exceed widely accepted max resolutions (1050p, 1080p, etc.).
In the design world it is not uncommon to find high DPI displays whose quality matches the prints that will be generated at the same scale. Perhaps you own such displays and can confirm that DPI settings do not change the size of raster images onscreen? There is also the issue of many web designer books written primarily by Mac users who often complain that the proper DPI for the web is 72 (the Mac standard, last time I checked) and warn Windows would-be web designers to check this setting. Why would they bother if it isn't an issue?
I'll grant you that even in the top case if image pixels are enlarged past desktop pixels' size, then the change in image's size should at least stay consistent relative to other images, although I've witnessed different programs handle it differently (some enlarging images while others seem to 'shrink' them - perhaps it comes down to viewing images who have different DPI settings?).
I'm sure you have better things to do than straighten my thinking on the matter out but I was curious as to how it all worked.1 Comment
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True, my printer comment was a bit of an oversimplification. Some applications pay attention to DPI and some don't. At any rate, DPI is meaningless in a Seadragon image... you get the pixels you've zoomed to. -
Inappropriate?Deep Zoom will not display images correctly if they have a DPI other than 96. Therefore, DeepZoomTools does a bit of work to force the output to 96 DPI.
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... because Silverlight's (WPF's too?) subpixel rendering always assumes 96DPI and resizes on other higher DPI displays based on the appropriate number of inches? I think I remember Ian Ellison Taylor say something like that in a WPF Boot Camp, but I could be off.
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Thanks , i zoomed in deepzoom images 10 times and what i observed is that image gets blured so there is some loss of pixels.Problem is how to maintain resolution after zooming in 10 times.I am dealing with the images having DPI > 600.
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Seadragon allows you to zoom in past full resolution, so it will definitely get blurry if you zoom all the way, even if there's no resolution loss.
That said, sounds like the DPI is having a negative impact. Can you convert your image to 96 DPI (don't resample, just change the DPI tag... you can do this with Image Size in Photoshop, for instance) and see if that makes a difference?
Perhaps you could share with us a side-by-side comparison of zoomed in sections of your original and the Seadragon version so we can get a better sense of the effects?
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