Reducing images for web

[shniks]

Hello everyone,
I was wondering, whats the best way to reduce big image files for posting on the web? I have tried reducing the file size and increasing jpeg compression but dont know the best balance between to two for optimal image quality. Lots of my photo lose their former glory ie they look pixelated and dull.
I have also tried batching, and am comfortable with this, so I mainly want to know the best size to reduce to, or any other tricks.
Thanks in advance!

[Laziferous]

I usually resize to 640x480. Before resizing, I apply the Unsharp Mask filter.

Amount - 150%
Radius - 0.3
Threshold - 0

Then apply it once again with the same settings after it's resized. I'm happy with the end result.

If you record those steps as an action (which I have), you can then apply it to a batch if you like.

I usually try to end up with a file size between 100k - 150k. Easy with a b/w shot, not as easy with color.

[Scottes]

JPEG compression really depends on each file. Certain images will show artifacts quite clearly if comressed too much. Images with sharp lines on a solid background for example, like a flagpole against a solid blue sky. Other image that are busy with many subtle variations of colors (a forest scene, for example) can be compressed quite heavily before showing artifacts.

Batch processing photos for web presentation is really a crap-shoot - I wouldn't recommend this, since every image is different.

Many programs have a type of "save for web" feature that lets you see what the results will be before saving. Photoshop calls it "Save for Web" while Paint Shop Pro calls it "Optimizer" for a couple examples. They allow you to see the resulting image while showing the resulting file size.

Without one of the above features it's generally best to save the image with several different compression levels until you find the smallest size with the best quality. DO NOT keep re-saving a JPG - things will get bad very quickly. Instead, open your TIFF, save as JPG, and close it. Open the TIFF again, save as JPG with a different compression level, and close it. And so on. Every time you save a JPG it goes through compression again, and you'll lose detail and add artifacts.

Eventually you'll get used to which images look good at which compression levels.

[ilya]

I'm absolutely impressed by the Web Presenter Pro by Fred Miranda. I have about a hundred different actions, some I made from tutorials, some I downloaded, and about four I paid for. This is the best $15 I've spent. In high sharpening mode, it even makes slightly OOF shots "seem" in focus.

http://www.robgalbraith.com/ubbthreads/showflat.php?Cat=&Number=206686&page=0&view=collap sed&sb=5&o=&fpart=31&vc=1

Disclaimer: I"m in no way associated with FM. Just sharing a happy experience

[dreamer]

i've found sometimes, saving the image as a gif can reduce a file. keep in mind it can also increase your image size.

normally its works when you only have less then the normal 256 colour used in your image. I find that the commpression in PS really is horrible and i use PhotoSTudio5.5 (got it with my scanner) which is excellent at commpression.

but it always depends on how many colours is used in your image and the complexity.

[dreamer]

i've found sometimes, saving the image as a gif can reduce a file. keep in mind it can also increase your image size.

normally its works when you only have less then the normal 256 colour used in your image. I find that the commpression in PS really is horrible and i use PhotoSTudio5.5 (got it with my scanner) which is excellent at commpression.

if you want to get photostudio, don't buy the programs it already aounr $80, if you get a canon scanner you normally get the software with it. and canon scanners are only abour $90, so its worth it to just get the scanner and get the program with it.

but it always depends on how many colours is used in your image and the complexity.

[w10d]

I see you're using PS CS, so you can take advantage of the improved resampling by using 'bicubic sharper' when reducing image size, (and 'bicubic smoother' when upsampling).

[shniks]

Thanks everyone :wink: , so much advice, I am going to give everything a go. Hopefully one day I will be satisfied enough with my pics to actually post one here. It will be a while, though, I still have much to learn, but you all are making it so much easier!

[4walls]

If you do not use the "save for web" option, then make sure you resample to 72dpi for the web and then change the dimensions of your picture as required.

Then use unsharp mask to get rid of the resulting fuzziness.