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Walter, I just don’t get your dpi comments.
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Ah. Interesting. Maybe that started the whole problem.
Good thing no one uses Premier Pro anymore! But I REALLY doubt they would still adhere to such an archaic and misinformed workflow…. I would hope.
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[keyframe] “To humor me, take an image (e.g., 2500 pixels x 2500 pixels, 600 dpi) that you created from a scan process. Name that file Sample_1.tif, for example. Now open the ‘scan’ file (Sample_1.tif) into Photoshop. Save that image to a new Photoshop file, Sample_2.psd, paying close attention to the save settings (file type, layers, etc.). Close Sample_2.psd. Use Finder to determine the file size (bytes) of Sample_2.psd. Open Sample_2.psd into Photoshop. Now, Save As to a new file, Sample_3.psd, using the same save settings that were used to save Sample_2.psd. I assume Finder will show Sample_2.psd and Sample_3.psd to be similar sizes (bytes). Now, for Sample_3.psd, use Image > Image Size to change document size–resolution to 72 ppi, making sure that ‘Resample Image’ is first unchecked. Pixel dimensions should remain unchanged. Look at Image > Image Size again to verify that ppi did change. Save Sample_3.psd on top of itself. Check Finder to see if the file size (bytes) of Sample_3.psd decreased dramatically or remained roughly the same.”
You’re describing essentially the exact same procedure we follow all the time. Scan Image large or create a very large dpi Photoshop element. Change dpi to 72 without resampling the image. Major file size reduction.
You get the same thing with high resolution photos. We take high rez photos of all the crew members of Good Eats for the animations, I believe they come up around 1200dpi. I drop all of those to 72dpi without resampling the frame size and they drop in file size about 50% to 75% as well.
Walter Biscardi, Jr.
Biscardi Creative Media
HD and SD Production for Broadcast and Independent Productions.STOP STARING AND START GRADING WITH APPLE COLOR
The new Color Training DVD now available from the Creative Cow! -
Walter, I sure don’t see the result you’re describing. Are you pulling our legs or are you perhaps also changing file type or file compression in your process? For example, a tif with the Zip compression option will be smaller than a psd file of same size.
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DPI’s talk about RESOLUTION. And this is a property of the hardware. An scaner have a certain resolution, a printer too, and a monitor too (vertical lines). In the end this shows the quality of the machine.
Pictures (stills and video) have DEFINITION. Number of horizontal x vertical pixels. And nothing else.
rafael -
[Tom Brooks] “or are you perhaps also changing file type or file compression in your process? For example, a tif with the Zip compression option will be smaller than a psd file of same size. “
I wondered the same thing.
The first time I tried to ‘test’ the dpi change, I was surprised when I got a dramatic size difference. Then I discovered the size difference I got was not due to the change in ppi (dpi), but was due to a difference in the way the TIFFs were created. I had created the original with the Grab screen capture program. I created the second TIFF with Photoshop. The TIFFs were not ‘created equally.’ If I took that second (Photoshop) TIFF and, using Photoshop, saved a third TIFF from it, I could now control file type, [lack of] compression, etc. more closely. The 2nd and 3rd files were now of similar size, though having different ppi.
Steve Grimes
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[rafalaos] “DPI’s talk about RESOLUTION. And this is a property of the hardware.”
Rafael is right on this one. DPI only matters when you are talkiing image size, as in a physical measurement. A one inch wide photo scanned at 300dpi will, obviously, yield a better image (and hence larger file size for a given type) than the same scanned at 72dpi.
Separate out the video world from the print world. 720×576 (or your NTSC equivalent) will ALWAYS be 720×576… if you then specified an DPI, this would merely let the printer know how big the final printout would be! 72 would be 10 inches wide…
The only time I worry about DPI is when scanning – you have a photo, you know its dimensions, you know how you’d like to translate that on screen. That’s when DPI is useful.
As to Walter’s experience, I can only say that if resampling is off, PS yeilds identical file sizes IN MY EXPERIENCE – YMMV!! Resampling on, yes then considirable difference as you’d expect. With resampling on you’re changing resolution with regard to image size, either up or down.
HTH
Jason
_________________________________
Before you criticise a man, walk a mile in his shoes.
Then when you do criticise him, you’ll be a mile away. And have his shoes.*the artist formally known as Jaymags*
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Even in a still camers, the dpi’s means nothing.When I change the quality of the stils in my Canon, what I change is the number of pixels of the picture. The camera keeps making the .jpg’s at 150dpi’s whatever the quality I set.
Rafel -
[Tom Brooks] “Walter, I sure don’t see the result you’re describing. Are you pulling our legs or are you perhaps also changing file type or file compression in your process? For example, a tif with the Zip compression option will be smaller than a psd file of same size.”
Nope, it’s a photoshop file to photoshop file.
Walter Biscardi, Jr.
Biscardi Creative Media
HD and SD Production for Broadcast and Independent Productions.STOP STARING AND START GRADING WITH APPLE COLOR
The new Color Training DVD now available from the Creative Cow! -
I tried Walter’s method, resizing from 400 dpi to 72 with resampling turned off and the resulting images were exactly the same size.
Lee Berger
http://www.leebergermedia.com
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