resolution and re-size

Hi all ,

Quick question, if I have resized an image and saved at 1500px width for web in PS, then I'm asked for a hi rez copy of said image (for print) can I simply up the rez in photoshop of the 1500 width image from 72 to 300 or whatever? does the fact that the image has been reduced mean that it's not really high rez? If I look at the properties the images does say 300dpi

Hope I'm not too confusing

Thanks

detox

When you resized the image to 1500 pixels then you did indeed decrease the resolution (the ppi figure at this point doesn't matter).

If you want a higher resolution image, you'd need to go back to the original. If you don't have the original, well, you can resize the one to a size in inches with a desired ppi value (such as 300 ppi), just realize that you won't be providing something of "better" quality.

It's kind of like taking a pic off the Web and trying to make a print with it, you can do OK with say a 4x6 print but try, say, an 8x12 print (or cropped to an 8x10 print) and what you get won't be so pleasing to the eye!

tonylong wrote in post #16909095
It's kind of like taking a pic off the Web and trying to make a print with it, you can do OK with say a 4x6 print but try, say, an 8x12 print (or cropped to an 8x10 print) and what you get won't be so pleasing to the eye!

Explain that to my FIL who copies my photos from Facebook and prints them and hangs them in his house or gives em' to other family members as gifts.

Bleufire wrote in post #16909140
Explain that to my FIL who copies my photos from Facebook and prints them and hangs them in his house or gives em' to other family members as gifts.

Hey, been there, done that, sure! And I remember "wincing" at those bigger prints, Oh Well!

The question would be as to whether the OP has the original shot/image (in the full resolution) or only has the one resized to 1500 pixels!

High resolution means only one thing, lots of pixels - 10 million, 15 million, 20 million - whatever your camera gives. 1000x1500 is 1.5 million pixels and changing the dpi, ppi or whatever won't change that. You can upsample the downsampled image, but you would be replacing all those thrown away high quality pixels with millions of computer guesses at what the pixel should be.

Bleufire wrote in post #16909140
Explain that to my FIL who copies my photos from Facebook and prints them and hangs them in his house or gives em' to other family members as gifts.

Beat him to the punch by making and distributing good prints.

The question would be as to whether the OP has the original shot/image (in the full resolution) or only has the one resized to 1500 pixels![/QUOTE]

Thanks all, yes I have the original but I was trying to save time. I process & re-size for web and then post on forums etc. However recently I've been asked for high rez copies and to make life easier thought / hoped I could just take the processed image and up the resolution. So it looks like I'll have to dig out the origonal and start from scratch

The images are at 72 and I'm being told they need to be 150 or higher for print in programs etc.

Thanks again.

detox

detox wrote in post #16909217
Thanks all, yes I have the original but I was trying to save time. I process & re-size for web and then post on forums etc. However recently I've been asked for high rez copies and to make life easier thought / hoped I could just take the processed image and up the resolution. So it looks like I'll have to dig out the origonal and start from scratch

The images are at 72 and I'm being told they need to be 150 or higher for print in programs etc.

Thanks again.

detox

The "72 ppi" figure is only an image "tag" that was assigned when you resized/exported the image for the Web. It does not refer to the "actual" resolution of the image.

The advice from the printer for "at least 150 ppi" refers to the fact that for a decent print, your image should have a "working/actual resolution" of at least 150 ppi. This may or may not be reflected in the "tag", but just realize that if you want, say, a 4x6 print at a resolution of 150 ppi, the actual image size in pixels would need to be 600x900 pixels, which would certainly "fit" your 1500 pixel Web image, but if you needed, say, an 8x12 print @ 150 ppi, then your image size/resolution would need to be at least 1200x1800 pixels. And you should know that the "150 ppi" figure is pretty much the minimum as to what is considered a usable print resolution unless you are making prints meant to be viewed at a considerable distance.

As I said, that 72 ppi "tag" really doesn't mean anything unless you are preparing an image to print using a process that "pays attention" to those tags. But for some print providers they may want to "see" the tag, in which case you can deliver an image with a tag that actually expresses the desired print size in inches at a "working" ppi resolution, so you could provide a 1200x1800 pixel image with a "tag" of 150 ppi designed for an 8x12 print at a "medium" print quality...

Bleufire wrote in post #16909140
Explain that to my FIL who copies my photos from Facebook and prints them and hangs them in his house or gives em' to other family members as gifts.

Haha I tell people this a lot. You don't need many pixels to make prints!

1500 pixels should be good enough to print up to maynbe 12" (maybe a little more) at a reasonable level of quality.

As said above ppi means NOTHING. What it does is controls the size of the print at a fixed pixel dimension.

At 300ppi your 1500 pixel image will be 5" along the longest edge.

At 150ppi the image will be 10" along the longest edge

At 100ppi you can now print at 15"

They probably mean you need to resample (add pixels) but doing that on a low resolution image is not really advised.

Always save your images at 300. Resolution has no effect effect on the screen and will not affect file size. You can save at 1 or 1000 and it will not effect screen resolution. Except for LR which is a whole new subject. I hate that subject.

Start at minute 8.

http://www.youtube.com …4mV3NsLmXw&feat​ure=relmfu

I'll bet I could get an acceptable 13x19 from it. Maybe even better than just acceptable, depending on the quality of the 1000x1500 and its past history. A dozen years ago I was able to produce very good 21x28 prints from Raws from a 5 MP Minolta (1920x2560) and the resampling I can do today would be better than what was available to me in 2002. Today I would resize to 20% more than my final size using LR resizing and output sharpening and then downsize 20% with PS's Bicubic Sharper. But I very much doubt that Bleufire's FIL goes to all that trouble.

Thanks again all, think it's a ps tutorial for me soon to clarify an acceptible image for print in a weekend race program for example could be 3000px width which isn't far off the size from camera "7D Medium" but would I have to change the rez from 72? I've had a few bits printed before but dont remember changing the resolution.
PS for dummies is my next purchase from smiths

Thanks

detox

detox wrote in post #16910710
Thanks again all, think it's a ps tutorial for me soon to clarify an acceptible image for print in a weekend race program for example could be 3000px width which isn't far off the size from camera "7D Medium" but would I have to change the rez from 72? I've had a few bits printed before but dont remember changing the resolution.
PS for dummies is my next purchase from smiths

Thanks

detox

It is very far off from what the camera is capable of. 6 MP instead of 18 MP. Why buy a modern high resolution camera if you could get 6 MP from a ten year old used 20D for a hundred bucks?

Forget that 72 dpi. As others have said above, it is meaningless and everybody ignores it. You can change it to 1000, but that won't change the image or the print you can make from it.

detox wrote in post #16910710
Thanks again all, think it's a ps tutorial for me soon to clarify an acceptible image for print in a weekend race program for example could be 3000px width which isn't far off the size from camera "7D Medium" but would I have to change the rez from 72? I've had a few bits printed before but dont remember changing the resolution.
PS for dummies is my next purchase from smiths

Thanks

detox

That "72 dpi/ppi" figure was put into the Exif by the camera as a "tag" because it's required to have "something" there with the standard jpeg Exif, but as has been said it's "meaningless" when it comes to our digital workflow and much of what we do with our images.

The cases where it can have some meaning is 1) Some print providers want a resolution value there that applies to printing, although the "72" put in by Canon is not appropriate... 2) When preparing a document in which you want to place images, the document is often set up using a layout in inches and given a "ppi" value and it can save confusion if you match your image ppi with the document and prepare the image with the needed dimensions in inches/ppi...and then 3) When you are preparing an image to print at a certain size and you want to "resample" the image to fit that print size at a specific resolution then you can use the ppi value. For example, if you want to size an image to print at 20x30 inches, you may want to resize it at, say, 300 ppi and then with the resized image you may want to apply some processing, say sharpening on the full-size image. However, for most digital processing and printing it really may not be needed.

Lightroom does have an "under the hood" Output Sharpening for printing that evidently does factor in ppi, so if you are Exporting an image for printing you are advised to set a higher ppi value, but by default Lightroom doesn't use the Canon 72 ppi, I believe it uses 240 ppi by default.