Batch converting from 240p to 72p

L

LittleMissK

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Edit My Images
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Hey guys,

Best way of going about this? Using CS5 if that's of any help! Have about 500 images to change and don't fancy going in to each one individually and altering it :/
 
Why do you need to do it? It's only a hint to the print process to figure out the size of output prints. It can easily be overridden at print time (in fact, most are).
 
Well they're products for a website - so would 72 not be a better way to have them at than 240?
 
DPI (or PPI) is irrelevant for web use. A pixel is a pixel. A higher DPI just means your image is larger on screen (because it has more pixels).

For web use, you just convert dimensionally. And yes, you can batch convert images.

Scripts > Image processor is a good place to start.
 
Martyn said:
DPI (or PPI) is irrelevant for web use. A pixel is a pixel. A higher DPI just means your image is larger on screen (because it has more pixels).
Click to expand...
I know what you mean, but it's a cdonfusing statement.

DPI matters only when you save images as a particular dimensional size - 6" x 4" where the program will calculate how many pixels in size the image needs to be depending on the dpi value. For example:

6" x 4" at 300dpi will save an image sized 1800 x 1200 pixels
6" x 4" at 100dpi will save an image sized 600 x 400 pixels

The images will then display as 1800x1200 or 600x400 on screen - so the 300dpi image would be 3x as big (9x in area) as the 600x400. You could change the dpi to any value you like in the saved images, and the images would still display at exactly the same size as PCs don't do any form of calculation of dpi for the screen.
 
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The DPI figure imbedded in the image data makes absolutely no difference for displaying images on the web. Both of the images below are 750x500 pixels, but the first is 72dpi, and the second is 300dpi. Both display at the same size on a monitor; any difference in size would only be noticed if they were printed using the resolution imbedded within each.

070.jpg


070a.jpg
 
exif says 2nd one res = 3000 px/inch
 
You're right, the second one is 3000. I set it that high to highlight that there is no point worrying about the imbedded dpi when saving files for use on the web. The first was left at 72 as it would appear that this is how most images come out of the camera. The only real discernible difference is a slight variation in file size, though I am not too sure why that should be the case.
 
Surely the 72 dpi helps deter people from making prints from web downloads.
 
haggis said:
Surely the 72 dpi helps deter people from making prints from web downloads.
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How? An image that is 800 pixels wide is 800 pixels wide, no matter how you hint to the print process you want it printed at 72dpi....
 
Sorry! Head now removed from bottom!

I usually set my web images to either 640 or 800 on the longest side as well as 72 dpi
 
:D No problems....
 
LittleMissK said:
Best way of going about this? Using CS5 if that's of any help! Have about 500 images to change and don't fancy going in to each one individually and altering it :/
Click to expand...

Hi, I asked a similar question a while back linky

I just recorded my action and then did a batch edit. It does open every single file and keep them open so maybe seperate them into a few folders and do them in a few smaller batches. But there is the close all function too.
 
haggis said:
Surely the 72 dpi helps deter people from making prints from web downloads.
Click to expand...

My images above should help to show that you can set the dpi figure to whatever you want. As far as web display goes it makes no difference. What is important is the actual size in pixels.
 
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