Photo Diet - help a digital newbie

Mar 15th, 2008, 02:46 AM
  #1  
aby
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Photo Diet - help a digital newbie

hi

need some tips on procedures for "thinning" pictures (of Kb's not Kg's) so they fit the primitive state of internet

i understand 72 dpi is the max for www

can you recommend a (freebie) software designed just for that?

should i use that huge Dinosaur = PhotoShop?? & how can i 'uncouple' the dpi drom image size ??

thanks in advance

aby, a dPhoto newbie
aby is offline  
Mar 15th, 2008, 04:47 AM
  #2  
 
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Hi aby

By no means am I a photo expert, but as no-one else has responded - I use apparently the huge dinosaur, Photoshop and for photos I post here on Kodakgallery, when I edit then save I use 2 (minimum) instead of 10 to 12 (maximum) which greatly reduces the kb's. Much quicker over the internet and still OK for people to get 6 x 4.

I am sure other advice will come in as the other countries wake up!

Kind regards

Kaye
KayeN is offline  
Mar 15th, 2008, 04:53 AM
  #3  
 
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Hi aby

Just tried it on a photo -

photo taken was 3.6MB 3264 x 2448

then went into edit and saved in date folder the JPEG options - in Image Option I chose Quality 2 (low) small file and closed and the photo is now 559.8KB still 3264 x 2448.

Hope this helps, otherwise wait for all those experts to come forth!

Kind regards

Kaye
KayeN is offline  
Mar 15th, 2008, 06:00 AM
  #4  
 
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i understand 72 dpi is the max for www

Hi aby,

Actually the dpi is meaningless for web images, it only has meaning when you print. The actual pixel dimensions are the first important setting, then the amount of jpeg compression (in other words an image that is say 600 x 450 pixels will look EXACTLY the same on the web whether the dpi -- actually ppi -- is set to 72 or 4000, but if you printed it at say 60 dpi it would be 10 x 7.5" and if you printed it at 300 dpi it will be 2 x 1.5").

For the web dpi is meaningless and ignored.

can you recommend a (freebie) software designed just for that?

I think all image editing programs will let you resize images (the first step), then you will want to save as jpeg with a mid-range setting. So as an example if you have a typical 6 mega-pixel image with say 3,000 x 2,000 pixels it is far too large to display on a screen or use for the web. So you might downsize this to say 600 x 450 pixels in the software (look up 'resizing' in the Help files for that program).

Now to save as jpeg you could try various quality settings, the higher settings don't buy you much but mean larger files, mid-range settings are typically OK quality-wise. As an example we typically start with 8 or 10 Mpixel files that are 24 MBytes or 30 Mbytes as tiffs, then downsize to at most 800 pixels on the longest side, then use Photoshop to make the jpegs, with a target file size of 50 KBytes ... I see a lot of images on the web that are 300 KB or 500 KB or even 1 MByte in size when people use too high a setting for the jpeg conversions, but all the images we have up at Pbase average 54 KBytes so this is easily attainable with minimal quality loss (if you know how to do it).

So settle on an editing program (Photoshop Elements is cheap and works fine if Photoshop is intimidating and too expensive, or there are decent freebies), learn how to re-size down and try different settings for jpeg compression and you're set.

Bill
Bill_H is offline  
Mar 15th, 2008, 07:39 AM
  #5  
aby
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Thank you KayeN
especially for checking again the exact "diet"
Seems the grand master has reduced it further to 1/10th

Bill_H
frankly, i'm shocked your pics are ~60kb...
thanks for correcting my ignorance about dpi (somehow i thought dpi was the resolution, but makes sense that it's for printing.)

i have access to PhotoShop, so i'll try the procedure you've recommended

other newbie(/ignorant's) questions:
Is there a difference when resizing RAW vs. JPG ??

using a scanner (i'm about to scan my slide collection) - is it advisable to resize using the scanner's program ? - thus saving time by having 2 sizes (one maximal) for every slide

aby




aby is offline  
Mar 15th, 2008, 07:40 AM
  #6  
 
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can you recommend a (freebie) software designed just for that?

aby, out of curiosity I just downloaded the free Google image editing program "Picasa" and ran it on one image ... this will do in one step what I suggested, ie, down-sample to smaller size and also let you control the jpeg compression.

So maybe give it a try (did I mention it's FREE). Once you have an image selected click on 'help' and type 'resizing' and I got this page explaining how to do it in one step ... http://picasa.google.com/support/bin...n&answer=13821 ... so anyway following these steps with a 'custom' compression setting of around 65 and setting the long-side to reduce to 640 pixels the file I used went from 3,504 x 2,336 pixels (24,000 KB) to 640 x 427 pixels at 40.2 KBytes, which is what you wanted to do.

So give it a try, a lot of people are using this program (when you install it DO NOT SELECT the option to let Google control your browser though) .

Bill
Bill_H is offline  
Mar 15th, 2008, 07:52 AM
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i have access to PhotoShop, so i'll try the procedure you've recommended

Oooh, if you have Photoshop forget the Picasa stuff I just posted ... in Photoshop first make sure you have the right working space, which should be sRGB for the web (if your file is AdobeRGB then the saturated colors will look dull and faded when you convert to jpeg and view on the web). You can change this to sRGB with 'convert to profile', the syntax depends on whether you have CS 3 or an earlier version. Try the 'help' files to find the command path for your version.

Anyway, convert to sRGB and then reduce the size with Image -> Image Size and enter a new 'width' or 'height' (for web files something between 500 and 750 pixels on the long side is typical) with 'resample image' and 'constrain properties' checked. For best quality for downsampling choose 'bicubic sharper' (not available on earlier versions of Photoshop). OK this gives you a smaller file with proper dimensions for the web.

Now to make the best jpeg do File -> 'save for web' (may say 'save for web and devices' on later versions) and in the new window that opens click on 2-up on the top row, which will show you the original and the one you are applying the compression to. Fiddle with the jpeg settings in the right-side panel, maybe start with 50 for Quality and adjust, you can see the effect on the file in the right-side window, also the file size is listed below the image. Try various settings, sometimes 40 or 30 or lower is OK for images without much fine-detail.

Anyway, this will let you reduce the pixel dimensions and then convert to a compressed (small) jpeg in two steps with a lot more control than you have in Picasa or the other freebies. Maybe try it with both programs and see how much better it looks with Photoshop?

Bill
Bill_H is offline  
Mar 15th, 2008, 09:32 AM
  #8  
 
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Hi,
Do you have access to an Apple Mac as iPhoto is very easy to use and will do all the resizing for you.
Otherwise Photoshop is very straightforward.
1. Download photos from camera and then open the required file in photoshop (it will probably be labelled something like IMG-123.jpg. You will see that the file size at the bottom of the picture is huge (many Mb).
2.Go to Image, then image size. A dialog box will appear. The resolution (dpi) should be set to 72. The document size should be changed to something like a width of 7 inches. Make sure the constrain proportions box is checked. This will give you a height of about 5 inches. You will now see that the image size at the top of the box will have dropped to much less that 1 Mb. However this will still be too large for a website to download quickly.
3. Go to FILE - save for web. Click the tab that says 2 up and you will see your original photo and one with a much smaller file size. You should aim to get this size down as low as possible but fiddling with the quality slider on the right side of the window. Compare the 2 images to get the best picture at the lowest file size. Save.
4. If you want to quickly see what the picture looks like in a web page, go to the browser you use (eg Explorer) go to Open File, select your new smaller picture and see how it looks.

Hope this works

regards

Barb
barbroy is offline  
Mar 15th, 2008, 11:17 AM
  #9  
 
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A popular, easy to use and free jpg viewing program is Irfanview - http://www.irfanview.com/
It does your basic viewing and thumbnails. Will also crop and resize and has basic color enhancement/correction controls.

regards - tom
ps - remember "cropping" is you new best photo friend
cary999 is offline  
Mar 16th, 2008, 07:34 AM
  #10  
aby
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Bill_H Barb & tom - thanks

i've already "thinned" some photos using PhotoShop. yeah it's down to about 50k...

Thanks for the freebies - i will use them as i'm a semi-nomadic computer user & i have it (PS) installed only in one place.

no, Sorry i haven't got an access to a Mac

Thanks again

aby
aby is offline  
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