Preferred technique for downsizing a photo?
Oct 13, 2021 11:49:06 #
TomHackett wrote:
Using Photoshop's Save for Web (Legacy) function, I was able to get below the 5mb limit by either setting the Quality (governs JPEG compression) to 83 (out of 100) or the Percent (number of pixels) to 76. Using the "blink test," I decided that the JPEG compression was just a bit sharper than the image size (number of pixels) reduction. It was difficult, really, to tell the difference.
The thing you have to be careful with when using compression instead of downsizing is that you can get color banding in things like skies.
Oct 13, 2021 13:23:43 #
I just use the jpeg slider to reduce to the desired size. But then, I'm 30 miles south of you on the Hudson so what can I know? LOL
Oct 13, 2021 13:34:57 #
Then again the 5mp size is mighty small and no matter what method you use you lose a good bit of detail. The "jury" probably just wants the small size to be able to shuttle it around for judgment. All applicants are under the same constraints so they would suffer the same conditions. I suspect the winner(s) would be asked to send a more detailed larger file size for display. The issue probably is composition of the photo, not the detail quality.
Oct 13, 2021 13:45:50 #
Oct 13, 2021 14:19:48 #
revhen wrote:
Then again the 5mp size is mighty small and no matter what method you use you lose a good bit of detail. The "jury" probably just wants the small size to be able to shuttle it around for judgment. All applicants are under the same constraints so they would suffer the same conditions. I suspect the winner(s) would be asked to send a more detailed larger file size for display. The issue probably is composition of the photo, not the detail quality.
I crop/resize all my "good" pictures from 6000x4000 to 1920x1080 for display on my big screen HD TV's. There is zero detail loss that I can see. I also resize them for my 28 inch monitor to around 1485x837 or so. This makes them fit the center of my screen allowing for desktop icons along the sides and top and bottom. The file sizes are all WAY under 1mb, and I don't notice any issues at all. Pictures of these dimensions need no addtional compression, they are plenty small with the camera's finest jpg compression.
My experience with digital displays is size them for the display aspect ratio, generally 1920x1080 and they will look perfect, and file size will be amazingly small. If I can't crop correctly for the aspect ratio of the screen, I'll resize to a size where both dimensions fit within the aspect ratio of the display. For this I mostly use FastStone, and will plug in 1920 for width, and if height is over 1080 I'll plug in 1080 and FastStone will adjust for the appropriate width. For Desktop I load the 1920x1080 pic in FastStone and punch in 1485 for width and it automatically sizes the height to around 837, maintaining the same aspect ratio of 1.77:1.
I never entered a contest other than a few on the HOG, but if I did, I'd want to know the display size and would try to go for that if possible. If I couldn't find out, I likely would double the size to fit perfectly in a 4K display, that way the aspect ratio would be exactly the same and the judges would have a nice image to judge.
Oct 13, 2021 14:35:39 #
revhen wrote:
I suspect the winner(s) would be asked to send a more detailed larger file size for display. The issue probably is composition of the photo, not the detail quality.
Actually, in this case the winners will print and frame their work. The JPEG I submit will be derivative from the original. I will print from the original (if I'm lucky enough to be selected).
Oct 13, 2021 14:43:54 #
Thanks, everyone. This has been a very enlightening exchange. I may not have THE answer to my question, but I now know better how to address it and will use the blink test frequently until I am satisfied with which option to go with.
Oct 13, 2021 16:15:31 #
DaveyDitzer
Loc: Western PA
CHG_CANON wrote:
This post was written to address this question: Recommended resizing parameters for digital images
I went there, watched it, saved it and am thankful to you.
Oct 13, 2021 18:09:37 #
DaveyDitzer wrote:
I went there, watched it, saved it and am thankful to you.
Thank you !
Oct 13, 2021 18:23:43 #
Using Affinity I can export a finished photo as a jpeg and select pixel counts on horizontal and vertical dimensions downward until I get the total MP count to the desired maximum, then save.
I'm sure other editing systems offer similar routines.
Mark
I'm sure other editing systems offer similar routines.
Mark
Oct 13, 2021 18:28:37 #
If you are using Windows then IrfanView can set an output size in the save dialog. Not sure if FastStone has a similar function. You can start with a tif and save as a jpg so there’s only one jpg compression involved.
Oct 13, 2021 22:09:23 #
revhen wrote:
Then again the 5mp size is mighty small and no matter what method you use you lose a good bit of detail. The "jury" probably just wants the small size to be able to shuttle it around for judgment. All applicants are under the same constraints so they would suffer the same conditions. I suspect the winner(s) would be asked to send a more detailed larger file size for display. The issue probably is composition of the photo, not the detail quality.
If the image size is reduced to standard display resolutions it wouldn’t take much if any compression to get under 5mg. Full HD is 1920x1080 or just under 3mp. With no compression at all it would be just over 8.5mg. So assuming that no two adjacent pixels were the same color it would be too big, but that’s rare. Most images would easily come in under 5mg at very high quality. As for needing a higher resolution display, that’s a no unless they were printing it. There is no advantage to having a file that is higher resolution than the display, unless you’re a pixel peeper that wants to fill the display with only part of the image.
Oct 13, 2021 22:30:03 #
So, it comes down to - in a 50% reduction - which is less detrimental - Bicubic sharper or JPEG compression ??
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Oct 14, 2021 12:07:37 #
imagemeister wrote:
So, it comes down to - in a 50% reduction - which is less detrimental - Bicubic sharper or JPEG compression ??
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I go for JPEG compression.
Oct 14, 2021 12:48:07 #
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