Johnny,
Save for Web is designed primarily for use with smaller images more typical of what would be used on the web. While it can be used with larger images, limitations may be encountered depending upon your memory resources. Further, it will set the resolution of the image to 72ppi which you may not desire. If you are saving a JPEG because, for example, you want to distribute it more easily by virtue of a smaller file size but you want to keep it as a very high quality file for printing, then I suggest it is best to use "Save As" rather than "Save for Web". Just ensure the image first has the resolution set as desired in the Image Size dialog, and then when saving, save it as a high quality JPEG.
Regards,
Daryl
Thanks, Daryl. I hadn’t noticed ‘save for web’ changing the ppi to 72, not what I want when the original is a digicam pic at 180.
On the ‘save as’ quality settings, is there a rule of thumb for what number to use to maintain the quality of the original? I realize that is not exactly possible since the original is a jpg and its getting compressed again as a jpg.
Should I just experiment with the numbers till I see a level that creates an image size approximately the same as the original?
johnny
Johnny,
Firstly, if you’re saving the image and space is not an issue, then don’t resave it as a JPG. Doing so runs the risk of reintroducing more JPG artifacts and further deteriorating image quality. Instead, opt for a PSD format or, if you need something more versatile across other applications, a TIF or BMP. Plus, a TIF can be saved with LZW lossless compression for some amount of space savings.
If you do resave as a JPG, recompression will be performed depending upon what kinds of edits you’ve performed. It’s easier to assume that is always done rather than try to remember what changes to an image affect JPG processing (that’s weasel-wording for "I don’t recall myself"). In any case, yes, basically select a quality setting that will give you something on the order of your original file size or larger. If the file is larger than the original, that may still be preferable since it means the edited file is not being compressed as much and hopefully will keep the artifacting under control. In the long run, a bit of trial and error should show you what you find acceptable.
Daryl
I hadn’t noticed ‘save for web’ changing the ppi to 72
It doesn’t.
ppi has no meaning on the web, only pixel dimensions are used. A 600×400 pixel image, for example, displays same size on the web whether saved at 72ppi or 7200ppi.
SFW doesn’t tag image for ANY ppi.
When you reopen a SFW image, most image programs default to 72ppi when there is NO ppi info embedded in file header.
Mac
I found something else that ‘save for web’ changes: the metadata. The images saved this way don’t have any metadata. These are digicam shots that have a lot of metadata.
I tried making some changes to one image, did a ‘save’ and ‘save as’, and both kept the metadata.
Since I’m not so concerned about saving storage space, I don’t see that ‘save for web’ buys me any advantage. I might as well use ‘save’ and ‘save as’.
johnny
One would think the name of the feature would be enough to answer that question.
Robert
I started this thread to learn if ‘save for web’ might be more versatile then just using for the web. I liked the fact that I could see a before and after of the image being saved. This makes it easier to experiment with more or less compression.
Since changing the ppi has no real effect (unless I’m missing something)on the pixel dimensions of the image or on the compression, perhaps saving for the web for general use is still a good option.
I wonder if a thread entitled "PS tools that do more then they were intended" wouldn’t be a popular thread.
johnny
perhaps saving for the web for general use is still a good option
I’d say no.
It would be a good way to loose any and all colour management since save for web also strips the colour profile (along with any other non-image data.
Ah! Well, this is why I asked. Thanks, Rene.
johnny
Johnny,
I strongly doubt the resolution of an image has any effect upon compression. The resolution is just information with which a file is tagged, so that the image pixels will be distributed with a density that produces a specific size of printed output. Apart from that, the resolution is meaningless and shouldn’t factor into compression.
Depending upon what you mean by "general use", SFW might suffice for most of your needs. However, if you ever anticipate future edits of the same image, you should save it in a non-compressed or lossless compressed format so as to avoid compounded degradation of the image each time it is is opened and resaved with lossy compression. Personally, I’d not routinely save any file as a JPEG that I’d anticipate printing or editing again at a later time. Storage of files on CDs is pretty darn cheap, so I don’t consider storage space an issue and will save files in a way that maintains maximum image quality.
Indeed, Rene’ made a good point too…I overlooked the other data that SFW strips from a file.
Regards,
Daryl
I liked the fact that I could see a before and after of the image being saved. This makes it easier to experiment with more or less compression.
Save as JPEG allows you a live preview of the image when setting the compression. Turn preview on and off, and you´ve got yer before/after comparison.
… save for web also strips the colour profile
If there is color profile in file, SFW gives you option to retain it, if that is only info one is concerned with retaining. And you can see the image size jump about 2k toggling it.
Mac
I guess I should point out what kind of pics I’m talking about. These are digicam vacation photos of a ski trip. A lot of the shots taken on the slope need some help to correct exposures. I don’t anticipate further edits beyond cropping and don’t plan on making prints larger than 4×6.
The first thing I do when I have a batch of photos like this, is to copy them to another directory which I name ‘edited’. These are the images I will adjust. The originals will never be touched.
Since I will be adjusting a large number of photos, and I don’t plan on spending a lot of time on each one, I will save as jpgs. Should I find myself spending a half-hour on a pic, I would save that one as a psd and a jpg.
My intent for this thread was to better understand the differences between ‘save as’ and ‘save for web’. I wanted to know which one would better preserve the content (after editing) of the original.
johnny
Depends on the size and output.
If you’re putting a low resolution image on the web, no matter how large it is to appear, use Save For Web for the best looking image at the smallest file size possible. S4W give you a side by side comparison so you can make visual choices on the fly about how much compression to use.
Save As is for creating a high resolution image for magazine submission or printing where you don’t want to compress the image or the Jpeg artifacts will show in the print.
Larry Berman