PPI and image size etc, Help!

treeman

treeman

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Mark
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I think I'm having utter brain failure today, but any help apreciated :)

I'm trying to thrash out a deal with a new client that includes me giving him large images to put up on Flickr (1024 px widest), that bits easy, but I don't want anyone to be able to get a good print from those images. So in my small brain I thought if the PPI was set to 72PPI the image quality when printed, would be pretty poor. I've just done some 8x6 prints at that size and they look perfectly fine, I've even tried one at 10PPI and it still looks fine :bang:

Am I completely barking up the wrong tree, and a 1024 px wide image is always going to print well to 8x6 regardless of the PPI?

Help!!!!
 
PPI (pixels per inch) is only relevant at the final printing stage. There is nothing you can do to prevent someone using whatever setting they want if they have your file and want to make a print. It's a printer driver setting, not one that lives with the image file.
 
treeman said:
Really? So when you save a file with a certain PPI setting, it's irrelevant?

624KB at 1200px wide
Click to expand...

Pretty much unless using printer settings. So if I know I want a photo to fit a 30" x 20" print at 180 ppi then I set that and it gives me 5400 x 3600 so printing at 100% will be a print that is 30" x 20". I could forget about the ppi and just select a crop at 5400 x 3600 pixels and tell it the dimensions I want to print (usually what I do). I only bother with setting ppi when sending something to a designer or similar where they will be playing around and need to know my intended size accurately.

The kb size of the photo isn't really important apart from showing it is good quality. The key thing is at 1200 pixels wide you can get a 200 ppi print at 6" wide which is plenty good enough for most people (300 ppi is the normal goal), some would be happy with a print a 100 ppi which is going to give a 12" wide print. At 150ppi you are still getting 8" wide with not a terrible resolution at all.
 
treeman said:
Really? So when you save a file with a certain PPI setting, it's irrelevant?
Click to expand...
Yes. Pixels are pixels. DPI/PPI is used to hint to the print process how big the thing should be printed. The user can override that.

Most print processes are 300ppi, a 1200pix image will print 4 inches across, but will take enlargement. I've printed 720 pixel highly compressed images at 10" with acceptable quality for family before now.
 
mark1616 said:
The kb size of the photo isn't really important apart from showing it is good quality.
Click to expand...

Not strictly true, if you use "Save for web and devices" when outputting from Photoshop you can reduce the "quality" setting significantly and still have a good "web viewable" image, the print quality is reduced too - as to whether it will prevent a decent 8x6inch print I'm not sure as I rarely print small sizes, always worth a try though!!

Simon
 
simonkit said:
Not strictly true, if you use "Save for web and devices" when outputting from Photoshop you can reduce the "quality" setting significantly and still have a good "web viewable" image, the print quality is reduced too - as to whether it will prevent a decent 8x6inch print I'm not sure as I rarely print small sizes, always worth a try though!!

Simon
Click to expand...

What I meant was, at 600+ kb it isn't going to be a problem. If it was 60kb then there would be loss of quality to both a printed image and also web. If it is artifact free and looking OK for web then within the resolution discussion we've had then it will still look OK in print.
 
Thank you all for your replies. It's not an area I've ever had to get involved with before, I can see why now! Looks like I'm going to have come up with 'plan b'. :)
 
simonkit said:
Not strictly true, if you use "Save for web and devices" when outputting from Photoshop you can reduce the "quality" setting significantly and still have a good "web viewable" image, the print quality is reduced too - as to whether it will prevent a decent 8x6inch print I'm not sure as I rarely print small sizes, always worth a try though!!

Simon
Click to expand...

mark1616 said:
What I meant was, at 600+ kb it isn't going to be a problem. If it was 60kb then there would be loss of quality to both a printed image and also web. If it is artifact free and looking OK for web then within the resolution discussion we've had then it will still look OK in print.
Click to expand...

The subject image I printed was 90kb and 720pixels on the long side and was sourced from Facebook from a small compact. I resized it from 720 to 3000 pixels on the long side and printed via DSCL. Whilst it doesn't stand up to rigorous inspection, it is perfectly acceptable for a 10x8 print and the person it was printed for was very happy (it was for family, taken by family and they couldn't find the original before anyone asks about copyright ;)).

To say that I was surprised what you could get away with printing from is an understatement....
 
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