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mborger
Joined: 12 May 2005
Posts: 4
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 Posted: Thu May 12, 2005 1:31 pm Post subject: JPG saving |
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Hello. I came back from a month in China with 1300 photos, which I've now cut to 650. I took them with a Nikon D70 at max JPG settings, so each photo is somewhere between 2.5 and 4.0MB. As I'm putting these up on a new web image gallery, I have a lot of editing to do. I'm running my usual routine of levels (usually auto) and cropping before I batch re-size them in IrFan for my Coppermine gallery.
The question is this. Obviously when I do my editing in Photoshop (the levels and cropping), I have to save them. I think the last time I did a "Save as" instead of just a Save, I chose the max setting of 10 on the JPG slider, which I think has now become the default for just choosing "Save" because the files are now INCREASING in size. So, for example, I open photo.JPG, which is 3.0MB, do my photo editing, and hit Save. That 3.0MB file is now 4.2MB. So...
1. Why does it make the file bigger? Shouldn't a setting of 10 only make it stay the same size or just slightly smaller? If JPG is about compression, why did it do the opposite and make the file size bigger?
2. Have I added unnecessary data and size to the photo? Has any data been added?
3. What can I do, going forward, to prevent this from happening? What is the correct method or recommendation for Saving As? As stated, I'm going to do the batch resizing in IrFan, so it's only the one Save operation that I'll be performing in Photoshop that I'm concerned with.
4. I looked in the Photoshop help and it says to choose Baseline Optimized for preserving colors -- I've been using the default of Baseline Standard. How much of a difference is there? Is it only noticeable on certain kinds of photos (print vs web, above certain pixel depth, etc.)?
Thanks. |
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cbadland
Joined: 19 Jan 2005
Posts: 962
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| Posted: Thu May 12, 2005 1:41 pm Post subject: |
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The question should be: why are you resaving as JPGs in the first place? Why not use a lossless format like TIFF? Every time you open and resave a JPEG you recompress the file and cause more image degradation. Hard drive space is cheap. |
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mborger
Joined: 12 May 2005
Posts: 4
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| Posted: Thu May 12, 2005 1:54 pm Post subject: |
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Well I guess I could make the initial save of the JPG after editing to a TIFF (all the photos from the camera were done as JPGs), but then they're going to get resaved as JPGs anyway by the batch software for publishing to the website. Your recommendation, if I follow, would eliminate one 'JPG save'. Is that the gist? |
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mborger
Joined: 12 May 2005
Posts: 4
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| Posted: Thu May 12, 2005 2:01 pm Post subject: |
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Wow, saving my 2.6MB JPG as a TIFF produced a 17.6MB file. I didn't check the LZW compression box. I guess that's ok as an intermediate step until the batch shrinks it down.
I'm using 5.0LE. I guess I don't have any options for running Auto-Levels as a batch/macro, do I? I have 650 photos to go through.  I think IrFan will at least take care of converting from TIFF back to a compressed JPG. |
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cbadland
Joined: 19 Jan 2005
Posts: 962
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| Posted: Thu May 12, 2005 2:20 pm Post subject: |
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Yeah, TIFF can get big!
If their final and only purpose is for web use, jpg away. But if you are keeping any files to have high quality prints made, definitely use TIFF with either LZW or ZIP compression, both lossless compressions.
(and check about upgrading to at least Photoshop Elements, PS 5.0 LE "loser edition"  is not what you want to best edit photos.) |
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mborger
Joined: 12 May 2005
Posts: 4
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| Posted: Thu May 12, 2005 2:26 pm Post subject: |
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Yeah, 95% of them are for display on the web, but my best ones I'll be blowing up to 8x10 and framing. So using LZW or ZIP compression on a TIFF doesn't hurt the image quality? Is there any reason not to use it, then?? Is one better? I purposefully didn't left the compression box unchecked cuz I figured it would hurt the quality the same way saving as a JPG would.
Btw, I'm using PS 5.0 LE cuz it's free on the computer I'm using.  Thanks for your help. |
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cbadland
Joined: 19 Jan 2005
Posts: 962
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| Posted: Thu May 12, 2005 2:44 pm Post subject: |
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I think LZW can be read by even older tiff readers, but neither hurt the image quality. |
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