Need help RE: printing requirements...ppi and pixels

[ice]

Hi Guys

My sister in law has asked if she could enlarge one of my pictures. I've never printed anything above an 8 x 10 and my knowledge of printing and ppi/pixel requirements are limited. She has asked for the below specifications:

"I’ve calculated that an image 2.46w (97”) X 3.45H (138”) would need to be approximately (97x250) + (138x250)= 24,250 x 34,500 Pixels but even 150ppi instead of 250ppi would do the job for me."

My query is - can I check in Photoshop what pixels/ppi my jpeg is, and would it print ok if the pixels/ppi are larger than her specs?

Thank you!

Imogen

[Granville]

You can go to the detailed properties (Get Info on a Mac) and find out how many pixels high and wide it is.

Then the way I understand it is that if you divide the pixel width buy the ppi on your printer, it will tell you how wide the image can be. Same with the height.

So an image that is 3072 pixels wide by 4608 pixels high, will print, at 150ppi as 3072/150=20.48 inches wide, by 4068/150=30.72 inches high.

At 250ppi it will print smaller.

The size as described above (24,250 x 34,500 Pixels) would be about an 836 megapixel image to have one printed pixel for each photo pixel.

There's an article here. I'm sure there are others.

[ice]

that was extremely helpful, thank you very much!

[ameerat42]

Hi Guys
...
My query is - can I check in Photoshop what pixels/ppi my jpeg is, and would it print ok if the pixels/ppi are larger than her specs?

Thank you!

Imogen

Yes you can, Imogen. I have version CS2, but yours should be similar. To check and change your image size, use the Image - Image Size command. Also, when printing, select Print Preview, set up the size and orientation of your paper, then use the scaling command, like "Scale to fit media". See the pics below as a guide.

Now, depending on how big your image is in megapixels, you may/may not have to re-sample your image. If you don't know what that means, yell out.
Am.

Printing 1
print1.jpg

Printing 2
print2.jpg

[arthurking83]

My suggestion is to not worry about the pixel per inch quality settings in Cs or LR or any other software you have.(leave all that to the printing service)

at 97" wide and 138" high .. your jpg is just not going to cut it any any pixel resolution other than for a billboard viewed from a hundred meters away(or so).

Firstly you want the raw file of this image. You then want to save it as a 16bit TIFF file in aRGB colourspace. One other step you could do is to upscale the image via Cs .. even by just a small amount prior to converting the raw file to a tiff file. even if it's only by 15% .. as long as you don't over do this stage, that 15% up sizing can make a small difference to the quality of the mural.

Judging by the cameras you have listed in your sig, a good quality printing service will probably explain to you that it should print well enough at the size requirement for viewing from at least 2-3m away .. ie. not inspected close up by a forensics team with a 20x loupe looking for exceptionally fine detail!!!

This is just my assumption, but I doubt that you have the ability to print a 3 meter by 2 1/2 meter wall mural on your home(or office) printer. Not saying that you don't have a fully capable printer, and in fact almost any printer can print such a print(albeit in many small chunks which can be placed together like any stitched image) ... but this will cost more than an arm and a leg .. so I'm assuming that a commercial printing service will be used here.

Realistically tho, a 3 meter print is usually printed at approximately 72ppi level of resolution, and going on this rate, your image needs to be approximately 6984x9936 in pixel dimensions, which is still a way off from your camera's specifications ... but probably just doable .. for example if this print is to be made on canvas.

If you(or your sister in law) wants to view the resultant print at close in distances and view fine detail .. well .... you better have exceptionally capable upscaling software.

Note if you don't have the image in a raw format .. I think you better convince your sister in law to either subdue the excitement of the image at such a large scale .... or prepare to view the image only from a way away.

[Mat]

It was explained to me by a printing service that you can view the final image size (after resizing) at 50% and the quality you see on screen is about what you will get in the final print.