I’ve concluded that with JPG compression, it’s always better to push compression to a lower quality rather than down sample an image. My tests have involved mostly high-frequency images (which I deal with more often). Particularly when output size or spec might be unknown, down sampling seems problematic at best. Obviously compression presents many of the same problems as resampling. Where is it best to take the hit?
Any opinions on the best method for getting on-disk file size down? Resample? Compress more? Objective analysis will be scoffed at but secretly absorbed.
Learn how to rescue details, remove flyaways, add volume, and enhance the definition of hair in any photo. We break down every tool and technique in Photoshop to get picture-perfect hair, every time.
Save ALL image files uncompressed at either their original size or at the maximum size and resolution that you are ever likely to use.
If you need lower resolution/compressed JPEGs for particular purposes (such as for the Web), save those separately, and in addition to, your original full-size files.
You can get 1 TB drives for about $130 so why try to economize on disk space?
If you need lower resolution/compressed JPEGs for particular purposes (such as for the Web), save those separately, and in addition to, your original full-size files.
Yes. All captures are stored as RAW and processed to TIFF or processed in camera and left on disk/backup as an original JPG.
I’m asking mostly about open-ended email transmissions, where I feel it’s still prudent to keep file sizes "reasonable". I’ll admit I’m not even sure I know what that word means. Our email system has requirements which make this particularly challenging (under 2 mb outgoing).
But my question still stands: is there any time at which resampling would be preferable to lossy compression to keep file sizes down?
And an excellent question it is.
It’s no secret that I avoid JPEGs as much as I can, but when I dofor instance to illustrate a point in a forum postI have come to prefer downsampling over compression, always. I did run some tests to compare this quite a long time ago. It was my conclusion that compression not only created the visible, clearly discerinble artifacts that we all have come to identify as "JPEG artifacts", but also resulted in wholesale averaging of colors.
Take this with a grain of salt, as I only resort to JPEGs when quality clearly does not matter.
All JPEGs are not the same. IMO one must test for the specific instance.
JPEG-12 compression of a well-shot image, for instance, may reduce the size of a TIFF file by 2/3 with no discernible difference on a 10×14 print. That makes JPEG-12 very appropriate for many electronic file transfers. OTOH lesser JPEGs can quickly destruct an image to unusability.
I know I can send at least 20MB attachments and someone sent me a 35MB attachment the other day.
You need a new ISP
A new ISP is not needed. An understanding of the inefficient transfer of files via email is needed. Limiting to 2MB is a sign that the mail administrator is quite bright.
People need to stop sending large files by email. Email only handles text files – so any binary file you transfer must be encoded to text (MIME). This results in an inflated file size. What’s the point in trying to compress to JPEG if you are going to blow the file up again via MIME?
Invest in FTP/HTTP services that allow you to post images, then announce the FTP/HTTP location to your recipients via email. By setting up a better workflow, you won’t have to nitpick which JPG compression method works best.
Most often I email a url. That always seems easier for everyone. "The correct file is up… now". But an unknown media partner who asks for an emailed JPG gets an emailed JPG, until I’m comfortable they’re comfortable with the alternative.
