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A complicated question on saving images.
So if given the space of 25mb to save a file, what is the best to save to this file size? A 100mb jpeg, a 200mb jpeg compressed greatly, a 75 mb Tiff saved in jpeg, a 50 mb Tiff saved lzw, or a straight 25 mb Tiff. All of these would end up as a 25mb file space. anyone have any info or anyone done any tests. You are about to take an image with a make believe digital back or scan from a chrome. You want to go to the sizes of 25 mb and 1mb sizes of what space the saved file will take up on a hard drive or cd. The file size has not been determined. But if I have a 1 GB file compressed to 25mb or 1 mb does that have more information than does a 40 mb tiff compressed to 25 mb or 1mb with LZW or Zip. What is the cutoff point where it is better to lose information from a larger file such as a huge jpeg compared to having a smaller file such as a Tiff(C-LZW) compressed very little? So if I have 25 mb of space on CD is it better to scan at 1 GB and then compressed to 25mb or to have a 40 mb Tiff compressed to 25mb? Maybe my logic is bad but there should be a cutoff point or maybe a graph where you could guess at the correct way to go depending on the type of image. Such as the simple with much white space or a complicated image. But the information you gave has importance for which compression forms are better for certain images without the added concern for readability. Jun 28 05 12:22 am Link The short of it is that the less compression the more information the file has, so the best way to save it is no compression at all. Of course that is not always possible so the next best thing is lossless compression which by definitoion is limited compression, the best of which in my experience is APS's PSD format. Jun 28 05 12:51 am Link Saving as TIFF using LZW (lossless) compression for the image and using ZIP compression for the layers will be about half the size of a PSD. But it's a slow save. Jun 28 05 07:10 am Link I agree with Xtreme TIFF LZW which will actually do the layers too but TIFF ZIP's are fine too. Jun 29 05 12:41 pm Link TIFF and PSD are good but consideration to what you will use the photo for after is a concern because some/all the file types will not consider this during compression. My rule of thumb is the largest file i can fit in the smallest will be better after i uncompress it than if i used a smaller file to compress. You always lose some quality when compressing/uncompressing files so try and look ahead to what you may use it for down the road. Jun 29 05 11:03 pm Link To what end will the file be used. Is it for archival purposes, print, client review? I have started saving my work in Adobe digital negative. Not too large of a file and it opens with their free software converter. 25 mg is a good size file for dng. Whoops, I forgot to mention that you would have to be using Photoshop CS or Elements 3 for this. Jun 29 05 11:52 pm Link Good replies so far but the question is sort of the how many licks does it take to get to the center of a tootsie roll pop. For there must be a cut off line where compression is better compared to other forms. Even with LZW compression, PS, or Jpeg compression, Where is the point where it is better to choose a 1000 mg file compressed to 25 mb compared to a 35 mb file compressed to a 25 mb file? Jun 30 05 01:54 am Link In my opinion it's always better to have the least compression you can get. That would be scan to 35 MB and compress to 25. The pic will still be looking great. If you scan on a 1 GB File (what kind of pic would that be anyway??) - you will have quality damage compressing it too much, since the compression will be in a digital way. You will have fractals inside, even if you save as TIF. Anyway - I wouldn't recommend a jpg compression if you want to touch the picture in any way afterwards. The quality will getting poorer each save. If you want to archive them TIF could be a good choice - without any compression. Jun 30 05 02:00 am Link Posted by marksora: Compress an image with jpg and then copy it into the original uncompressed image in a new layer in photoshop. Select difference as the layer mode. See the difference? The higher the compression, the more you see. Jun 30 05 02:29 am Link Just looking for a pie chart or graph. Jun 30 05 02:31 am Link A JPG works for me. Saved at it's highest quality, I can't see the difference between it and a TIFF so I use JPG's even when uploading to my lab for large prints. Paul Jul 01 05 10:16 am Link Posted by marksora: In addition to photography, I am also a graphic artist so I work with stock houses buying images from them and I work with printing press plants all over the US. Jul 01 05 05:36 pm Link jpeg compression is variable to the amount of difference amongst pixels in a specific image, so in addition to the other responses, I don' think you can boil it down to a rule. I think your real question would be, given a final output size goal, which would be more degrading to an image, upsampling a lower res source file? or compressing a higher resolution one. You'd need to know your endpoint to decide- I'm a die hard raw format/tiff guy- the only time I use jpegs is to upload to MM and musecube- the real solution is BUY MORE STORAGE. Jul 02 05 01:08 am Link the specific answer depends all on the fiture use of the image. suffice to say as a 25Mb .tif ! i find that ~80% to JPG is about the best ballance. i would save them .tif as big as your scanning them. who's scanner u using? i scanned a $50 3200dpi to yield a 550Mb file, nearly takes everything my puter will handle but its still not more than an 8bit image so a 100% JPG isnt anything and the file is reduced by a fifth or so. jpegging converts everything to an 8bit data file anyways... Jul 02 05 03:31 am Link |
