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-   -   Getting a picture below 200k in Photoshop (https://www.trekearth.com/forums/showthread.php?t=1916)

AndrewGarn 05-10-2004 10:57 PM

Re: Getting a picture below 200k in Photoshop
 
I agree, a very useful thread. Thanks to kajenn for linking it to me :-)

fightingillini 03-11-2008 05:14 PM

Re: Getting a picture below 200k in Photoshop
 
"First, I resize the picture to the final size using Image/ImageSize - make sure that Constrain Proportions is checked, and that ResizeImage is checked and set to Bicubic. Type the size you want for the long edge, and the other axis will be resized accordingly."


What Image size do you recommend?

Didi 03-11-2008 06:04 PM

Re: Getting a picture below 200k in Photoshop
 
Bigger size it's better until 800 pixels large.

AdrianW 03-14-2008 09:04 PM

The 2008 remix
 
A simple Photoshop workflow can be found <a href="http://adrianwarren.com/pstutorials/pb/">here</a>. It's pretty straightforward, and you can split it into steps as follows:

First, <a href="http://adrianwarren.com/pstutorials/pb/imageediting1.shtml">apply colour correction</a> and curves if required. It's better to do this the full-sized image.

Now <a href="http://adrianwarren.com/pstutorials/pb/imageediting2.shtml">rotate the image</a> if it needs straightening.

This bit isn't mentioned in the tutorial: Then I resize the picture to the final size using Image/ImageSize - make sure that Constrain Proportions is checked, and that ResizeImage is checked and set to Bicubic. Type the size you want for the long edge, and the other axis will be resized accordingly. The current TE spec allows an image to be a maximum of 800px wide, so if you're happy with people being able to use that size, use it! If you're concerned about image theft, go smaller, but make sure you mention in your note why. 500px is less useful from a theft perspective.

Next <a href="http://adrianwarren.com/pstutorials/pb/imageediting3.shtml">sharpen the image</a>. Look at a section (or the whole image if possible) at 100% magnification, and select Filter/Sharpen/SmartSharpen. I select LensBlur from the dropdown, then a radius of 0.9, and amount of around 75%. The precise settings vary depending on the original image; sometimes those settings will oversharpen, sometimes they'll undersharpen. So you'll need to watch for haloes appearing around sharper edges, that's a sign you've oversharpened the image - if they appear click Undo and try again!

Finally I choose File/<a href="http://adrianwarren.com/pstutorials/pb/imageediting4.shtml">SaveForWeb</a> - this enables you to see what effect your JPEG settings will have on the final result. I use the "2-Up" view, because it allows me to compare the original with the compressed version. Select JPEG, then select a Quality of 65 (Blur 0), and make sure that Optimise is checked. Now gradually reduce the Quality setting - look at fine detail, and any sharp edges in your image - if you reduce the value too far artifacts will appear around edges, and fine detail will disappear. Most of my images are saved somewhere with a quality of between 50-65. When you vary the setting a filesize will be displayed - if it's below 200k you're done! Now remember to click Save, and give it a new filename - overwriting your original image is a very bad idea... As Yuri suggests in PhotoshopCS and up, you can choose a filesize.

KiiT 03-22-2008 07:59 AM

Re: The 2008 remix
 
This is very helpful.

One thing though, whenever I save via SaveForWeb (still on PS6, Quality 75~80)
the thumb image looks fuzzy maybe not so much on TE but definitely in the picture folder on PC.
Is this normal?
Although it is not critical, it is bothersome..

Didi 03-22-2008 08:01 PM

Re: The 2008 remix
 
Hi Adrian
I never use Save for the web to preserv the Exif file and my picture are between 164 and 198 Ko
Regards

AdrianW 03-26-2008 01:45 AM

Re: The 2008 remix
 
Yes, you can get files the same size using SaveAs, but the quality will be lower with the same end filesize. Not least because all that EXIF data has been removed ;) It takes but seconds to set the aperture and exposure in the upload window afterall! A quick test shows around 6kB per image is saved, but those were already sRGB images, so that doesn't include the ICC profile size.

However the most important reason to use SaveForWeb is that the files get converted to sRGB during the SaveForWeb process (if you uncheck ICC profile), which means that everyone should see the same result assuming their monitor is calibrated correctly.

That doesn't happen when you do SaveAs by default, so you run the risk of random colour/contrast/gamma variation depending on which browser is used, even if all the target systems are calibrated.

The problem is that some browsers are profile aware, some aren't. Some systems are profile aware, some aren't. If you're all using the web colour space (assumed sRGB) then your images will appear the same regardless, assuming the systems are calibrated. Not so when you use SaveAs. That's why I recommend the use of SaveForWeb for web images.

I also don't like putting my EXIF online; as it exposes all manner of things, including your camera serial number etc. That's a personal thing though.

AdrianW 03-26-2008 02:01 AM

Re: The 2008 remix
 
Kei, not quite sure what's going on there. What happens when you look at the image itself, is that OK? If so I suspect it's related to the thumbnail images being removed during SaveForWeb, but I've never noticed a problem here under Windows Vista. Then again, I rarely use thumbnail views as they slow any system down.

Basically there are three major things that happen differently when you use SaveForWeb; the first is that any EXIF data is removed (which has no impact on image quality), the embedded thumbnail image is removed if present (I suspect this is the problem here), and finally any ICC profile is removed as the image is converted to sRGB. All three result in smaller files.

Whatever's happening, please make sure you don't overwrite your original images!

KiiT 03-27-2008 03:07 AM

Re: The 2008 remix
 
Thank you Adrian, the image opened from the fuzzy thumb looks just fine (on XP).
Did I need to check Progressive? I remember it was unchecked when I tried.

Right, whatever it is I can live with that, as long as I secure the originals un-messed..

AdrianW 03-27-2008 05:41 AM

Re: The 2008 remix
 
Kei, I doubt Progressive will make a difference to the thumbnails in any way. Checking it often makes the images fractionally smaller though. It varies from image to image.

If I'm right it's the lack of the embedded thumbnail that's the key here. The only way you'll get the embedded thumbnail back is to either use SaveAs (not recommended), or you could use Exifer to recreate one if you just want to confirm it.

If you're interested in confirming it, download <a href="http://www.exifer.friedemann.info/">Exifer</a>. Then find one of the images you've used SaveForWeb on that has a fuzzy thumbnail. Should be fairly easy to do as the icons won't have an image on them when viewed in Exifer. Right click on one, select EXIF/ITPC then Thumbnail and then CreateThumbnail. The file should now have a small version of the picture itself on it when viewing the folder within Exifer. Quit Exifer, then have a look at the file from XP directly, is the thumbnail sharp now?


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