Resolution and Printing size????

rickp

I ahve a friend that has some images on photobucket that where converted from RAW to JPG before uploaded. Now the image resolutions are 72dpi. She wants the images to be 300dpi so she can print them at a size 4x6. Does she really need to change the images to 300dpi or will the current resolution print good 4x6 images? Also what is the max size she will be able to print with the 72dpi?

Thanks

R.

arodney

rickp wrote: »

I ahve a friend that has some images on photobucket that where converted from RAW to JPG before uploaded. Now the image resolutions are 72dpi. She wants the images to be 300dpi so she can print them at a size 4x6. Does she really need to change the images to 300dpi or will the current resolution print good 4x6 images? Also what is the max size she will be able to print with the 72dpi?

The question is, how many pixels does she have on both axis. The DPI setting only tells an application how many to device up to make that print. So 300dpi isn’t really necessary although you can change that. How many total pixels does the image have length and height. For example, say you have 2000x1000 pixels. At 1000 pixels per inch, you get a 2x1 inch print. At 300 pixels per inch 6.6x3.3 inch print. Divide up the pixels you have by the pixels you want to output. IOW, the resolution is just a tag that tells us how many pixels to divide up for a fixed size on output (digital images don’t have a “size” other than the volume they take up on a drive).

In Photoshop, Image size command, click off the Resample button. That tells Photoshop not to add or subtract pixels. Change the resolution field from 72 to 300 and click OK. No pixels are added or subtracted, this only changes the math used to tell the user what “size” the image could be if output using all those pixels using that math.

jyarbrough

Not sure if this is how to ask a question related to the thread but here goes. How do I have SmugMug or any other photo printing outfit print to an exact measurement. Specifically I need the printed results to be 7 inches wide by 17" tall. I formatted it thus in PhotoShop but SmugMug gave me a 8 by 18 inch result based on their paper size. I can crop but I would rather get an exact size.

jfriend

jyarbrough wrote: »

Not sure if this is how to ask a question related to the thread but here goes. How do I have SmugMug or any other photo printing outfit print to an exact measurement. Specifically I need the printed results to be 7 inches wide by 17" tall. I formatted it thus in PhotoShop but SmugMug gave me a 8 by 18 inch result based on their paper size. I can crop but I would rather get an exact size.

It is very difficult to get an exact size with any printer other than your own because printers expand the image slightly to make sure they cover all the edges with the image and sometimes to allow a little room for trimming the paper.

Since this bleed is not a precise measurement, it's impossible for you to generate a finished result that is an exact reproduction size.

The best you could do at Smugmug is to put your image on an 8x18 canvas (with extra white around it leaving yourself a 7x17 image inside) and plan for a slight bleed expansion (perhaps 1/8" on each edge). Then, print that onto 8x18 paper and trim the extra white borders down to result in a 7x17 image.

The reason I own a 17" wide printer is exactly for this scenario where you can control it 100% yourself. I realize that isn't a wise economic choice for most, but it's the only way I know of to really control the print size. I've found this situation arises when you have to fit into a pre-made frame and your image has no extra room along one edge and you can't afford to give up the bleed that normally happens.