Photoshop Help (1 Viewer)

Saphire · Nov 14, 2005

Can anyone tell me what is happening with photoshop.
I work on an image, levels sharpening etc. I get everything just the way I like it and it looks good on screen. Go to save for the web and the photo's look flat with no life, so I have to go back and give extra sharpening, contrast and satturation just to make it look better for the web, am I doing something wrong.

RAH · Nov 15, 2005

Several things come to mind if you are saving for the web. Perhaps you are using too high a compression level (low quality jpg), so you are picking up a bunch of jpg artifacts on the save.

Also, I don't know how "save for the web" works, but does it also reduce the size of the image, say to something like 800x600 or lower? If so, and you reopen it to look at it, your viewing software may be then enlarging it to screen size and making it look all washed out. Make sure when you view it that you are viewing it at no higher than 100% zoom level.

Saphire · Nov 15, 2005

Thanks, I do a basic save usually around 700 the largest dimension for saving to birdforum, with a quality at the highest that will give me around 100k. The image doesn't look the same as the original they look flat. I tried the saving to web without doing any adjustments to size or quality and then re-opened in photoshop with the original to compare and they are totally different. The original is vibrant in sharpness and colour and the other flat as if I hadn't done any editing.

Andrew Rowlands · Nov 15, 2005

Saphire said:
Thanks, I do a basic save usually around 700 the largest dimension for saving to birdforum, with a quality at the highest that will give me around 100k. The image doesn't look the same as the original they look flat. I tried the saving to web without doing any adjustments to size or quality and then re-opened in photoshop with the original to compare and they are totally different. The original is vibrant in sharpness and colour and the other flat as if I hadn't done any editing.

Just a thought, Christine - can you edit and save (as a copy, if you like) with minimal or no compression then reopen the edited copy; does it still have the vibrancy? What if you save to web from this?

Cheers,

Andy.

SeanKP · Nov 15, 2005

Saphire said:
Thanks, I do a basic save usually around 700 the largest dimension for saving to birdforum, with a quality at the highest that will give me around 100k. The image doesn't look the same as the original they look flat. I tried the saving to web without doing any adjustments to size or quality and then re-opened in photoshop with the original to compare and they are totally different. The original is vibrant in sharpness and colour and the other flat as if I hadn't done any editing.

Hi Christine

I had to play around with the 'save for web' settings before I was happy with it. From memory, I think the biggest difference was made by adjusting the the method used for compression. I think I've got that set to bicubic but I'll check when I get home.

Sean

robski · Nov 15, 2005

A quick tutorial on Data Compression

I have never used the save as web option so I can't give advice on the best way of using it.

Basically Save to web is aimed at giving you a reasonable image with a reduced file size.

Elsewhere you have read that lossy compression methods works by throwing information away from the orginal image. With experience it becomes easy to gauge how well a file will compress. So How does Save to web degrade the image.

The first compression killer is the amount of detail in an image. The higher the level of detail the less it will compress by.

The attached examples 1, 2 and 3 are the same image size with increasing amounts of detail information. All Examples are Max Quality JPG files.

The flat colour image compresses the best to 21Kb.
The second image has a few transitions and compresses to 29Kb.
The third image has more transitions and compresses to 53Kb.

So to improve compression an option is to throw away some of the fine detail.

The second compression killer is the number of colours. The higher the number colours the less it will compress by.

Attached examples 4 and 5 are the same image size but one has 256 levels and the other only 6.

Example 4 has 256 levels and compresses to 55Kb
Example 5 has 6 levels and compresses to 42Kb.

Again an option to improve compression is to reduce the number of levels and colours.

This is why noisey images benefit from noise cleaner programs for increased data compression by reducing the random detail and colour.

Robert

RAH · Nov 15, 2005

Saphire said:
Thanks, I do a basic save usually around 700 the largest dimension for saving to birdforum, with a quality at the highest that will give me around 100k. The image doesn't look the same as the original they look flat. I tried the saving to web without doing any adjustments to size or quality and then re-opened in photoshop with the original to compare and they are totally different. The original is vibrant in sharpness and colour and the other flat as if I hadn't done any editing.

It is very surprising that they are "totally different," implying a drastic reduction in quality. Unless you have a tremendous amount of compression going on, it shouldn't reduce the quality all that much.

However, perhaps it is saving them as .gif files? If this is the case, you would get a DRASTIC reduction in quality, because gifs are limited to 256 colors.

Another thought is perhaps "save for the web" saves the original file, not the modified onscreen version? This sounds ridiculous, but from your description, it kind of sounds like that. Perhaps you could experiment by making a really obvious change - like use the text tool to write "hello world" across the image, then do a save for web and see if the text is there on a reopen.

Another thought - are you sure that save for web is not putting your result file into a different directory, and then you are just reopening the original file - not the modified one - afterward? An obvious way to test is to make sure you change the filename on the save for web.

Otherwise, it is hard to account for such an extreme change in quality.

Saphire · Nov 15, 2005

Andrew Rowlands said:
Just a thought, Christine - can you edit and save (as a copy, if you like) with minimal or no compression then reopen the edited copy; does it still have the vibrancy? What if you save to web from this?

Cheers,

Andy.

Andy I have tried what you said the first photo is just resized and saved with Maximun compression. The second was done saved to web with maximum compression. Hopefully it shows the diference in the photo's.

Saphire · Nov 15, 2005

Andy. I have just done another comparison I had both attachments open and the one in Photoshop had all three together, the one untouched in photoshop is still more vibrant then the two I have posted, so it looks like as soon as you reduce the file with whichever method you use you lose quite a bit of quality.

Roy C · Nov 15, 2005

I never bother with 'save for the web' myself. I get better results by resizing to 700 or 800 pixels and then doing a 'save as' at about a medium jpeg compression (5 or 6). I have tried the save for web option but have never got good results.

Saphire · Nov 15, 2005

Hi Roy. I am beginning to come to that conclusion whatever save to web does it seems to degrade the files to much.

Andy Bright · Nov 15, 2005

Saphire said:
Hi Roy. I am beginning to come to that conclusion whatever save to web does it seems to degrade the files to much.

What version of photoshop do you have? There shouldn't be any difference from the results of either method of saving. Do you have the side by side before and after view? This should show you the effect of any compression.
see example below (from CS)

Saphire · Nov 15, 2005

Andy I am using CS2.
I wouldn't have thought there should be much of a diference, for some reason there is, I am just about to upload another into the gallery done by the basic resize then save as Jpg Quality 10 in the main window, just to see whether this is a better way of doing it. I have been using the save to web as both the resize and the quality are all in the same window to me this is easier to do. I have had to cancel quite a few times to go back to the original to give more contrast and sharpness because as soon as I open the save to web page the image seems to hve lost some of its depth.

Saphire · Nov 15, 2005

Just had a look at the above photo I have posted. I have the original in photoshop at the moment and comparing the two the one in photoshop is richer and sharper. I could understand if I was viewing the image on a diferent monitor, confusing. The only other thing I have thought of doing was to alter the calibration in photoshop to match the web so at least any alterations I do it should look the same.

Coaldust · Nov 15, 2005

I don't know what in camera profile your using but all images display best when converted to sRGB for the web, if you upload an image in aRGB it will have a flat appearance.

robski · Nov 15, 2005

Andy

This shows the amount of information thrown away to get your file down from 600Kb to 26Kb. I have lightened the difference image to make the differences more obvious. Just goes to show how the eye/brain can be fooled.

I have also done the same for Christines image. There is a 64Kb reduction in file size between her 2 files. Something has to go to achieve this.

Is it a case of we want our cake and still eat it ?

Robert

Saphire · Nov 15, 2005

Thanks Coaldust. I have just come across the assign profile under the edit menu if I set it to working rgb then both photo's look the same, now all I have to do is hopefully to set-up photoshop to assign that profile when I open an image then when I do the save to web bit they should be identical.

robski · Nov 16, 2005

Christine

I don't think you have the full story yet because the setting you have found relates to photoshop only ( which and how ICC profiles are used) When you save as web the image is passed to image ready software. I have found a setting in there related to profiles. If you right click on the image you get a menu. My default setting was uncompensated color which strips out the icc profile correction from photoshop. If you select use document colour profile then it applies it and the image looks the same as the photoshop version.

Robert

Saphire · Nov 16, 2005

Robski. I have just done that and it works. Thank you! I didn't even Know about those settings, now the file looks exactly the same. I was beginning to think because of the amount of loss when you reduce the file that was the way it finished up.

Saphire · Nov 16, 2005

I now have the save for web with 4-up, you can see the degradation in each picture as the file is reduced in size. Pressing profile correction on each one has put most of the saturation back, the images are degraded as the file size gets smaller but I expected that. I think I now understand. Thank you again and hopefully this will help others to understand how and what happens when you reduce a file.

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