High res photo help

4R Graphics

Active Member
Ok heres the question I have a 8 mega pixel camera the high setting is 3264X2448 pixels and the output is 11inX16in which is 176sqin so this works out to 45,399 ppi correct? so if I blow this up to a 150 dpi pic the image would be roughlly 369sqft? This does not sound right could someone explain and break down the dpii and camera resolutions and what not also when I open a new file in photoshop I am asked what size and dpi I assume I go to what ever size by whatever dpi I want be it full size or 1/4 etc then import the pic that is stated above and scale it to the size I want to fill the canvas? I am wanting to get into the digital print stuff but I will use a wholesaler for the print work but I will do the design so I need to figure this out please be gentle but detailed in your reply.

Thanks for the help.
 

Fred Weiss

Merchant Member
DPI stands for Dots per Inch and is intended to describe output sizes when sending to a print device.

PPI is very similar and stands for Pixels per Inch. It is intended to describe the resolution of the digital image.

Your original image of 3264X2448 measures 45.33 inches x 34 inches if you set the PPI to 72. The same image is 32.64 x 24.48 if you set the PPI to 100. At 300 PPI the image measures 10.88 x 8.16 inches.

Your printer can tell you what resolution he would like the image ... 72 PPI, 100 PPI etc. He then sets the output for the RIP to the printer (DPI) at whatever quality of resolution the job calls for.

We have found for most jobs that a PPI of 100 at the full size needed for the print is a good choice for most images.
 

4R Graphics

Active Member
Fred thanks for the reply but you said set the ppi to 72 or 100 so with the settings of my camera 3264X2448 I can set a new canvas in photshop to 72ppi and set the size to 45" x 34" and bring in a photo with the 3264 x 2448 settings and have a good quality print ie vehicle wrap quality or perhaps a persons face on the side of a truck quality? I assume that I can blow this up 200% with one of the photshop plugins that scale photos and still have a reasonable quality pic? I ask because I have had a few people ask if I could take a photo and print it large scale and well I wasnt sure and dont want to look stupid to the customer.

So I take the resoultion ie 3264 x 2448 and divide the numbers by what ever resolution I want the final product at and that gives me the largest size it can be scaled with out software blow up tricks?

I am still kind of confused on the ppi dpi thing when it comes to the printer tell me if I am correct here but if I am outsourcing the print work then I really only need to worry about the PPI and the print shop will do the rest? So I need to design in say 100PPI or better and I will have no problems with really bad pixilation issues?

Thanks for the input!
 

dman0427

Member
Your last statement sounds right to me.
I usually design things at 100% to scale @ 72-100 ppi
Anything Higher is really unnecessary.

So create a new doc, enter measurements (actual size), set the res to 72-100, and you're good.

Your 8MP camera should be just fine.
 

Fred Weiss

Merchant Member
As to enlarging your photos (technically increasing your pixel dimensions), my experience is that you are generally safe up to 400% enlargement. Above that the amount of pixelation or other undesirable effects will depend on the nature of the photo and the use of a product like Genuine Fractals or BlowUp.
 

4R Graphics

Active Member
Fred,
400% with out a prog like blowup. I figured you would be able to go no more than twice the size of the original ie 100ppi max size X 2 with out getting a bad pic. I realize some stuff wont be able to scale that large but man this is great so a 8 meg camera set at highest setting can realisticlly do a persons head and scale it large enough for a semi trailer. I was thinking there was going to be no way with out some super expensive pro equipment or a photographer thats expensive. Thanks again Fred for the info I still dont get the ppi to dpi but I guess I dont need to until I get a printer and then printing at different settings will teach me what I need to know.


Thanks again.
 

mondo

Active Member
ppi or pixels per inch is the tiny square thing you see on the image. Let say for example there is a one Jim Carrey movie poster that has a lot of pictures and when you look at it from a far you see Jim's head but when you look at it close you see little square of pictures. dpi or dot per inch is what the printer nozzle spray but this was explains to me a long time ago when printers are capable of just printing under 360 dpi max. Printers today are different they print better dpi than it used to be so I might be wrong on the dpi part.

I also do 72-100 ppi when doing images on the computer but if do like vector or any line drawings on photoshop I do it on 150 ppi minimum. Hope this helps. Cheers!
 

Fred Weiss

Merchant Member
Look at it this way ...

PPI is for your source image and DPI is for your output print. People tend to use the the two terms interchangably because they both refer to the number of pixels in a square inch.

When we are talking about editing the source image, PPI is correct and our goal is to size it well enough so that it carries enough information to give us a good result when we print it. There are certain limitations we reach in image editing beyond which we run the risk of creating distortions.

When we are talking about outputting the source image to a printer, that image is processed through a RIP at whatever DPI settings we want the printer to laydown ink on the vinyl or other substrate on which we are printing. That same image with a dimension of 9" x 12" at 100 PPI can be used to print an image measuring 9" x 12" at 360 DPI or an 18" x 24" image at 720 DPI. The results will vary and there are limitations in this as well but that is what the RIP does ... manipulate the data that the printer outputs. And it does it using DPI.
 
I like to use "Blow UP" its a filter that will let you resize images, works with CS2 and up and PS Elements...very simple and smooths out all those bit map chunkys...
 

4R Graphics

Active Member
I greatlly appreciate everyone who has chimed in on this post I have learned and I believe that I have a fair enough understanding to get reasonabbly good quality prints for my customers so thanks again everyone. I have to tell you i was kind of expecting to get some burn remarks as to newb go home stay away from print newb but man this was great and a couple of others even bumped I hope everyone learned something.:thumb:


Thanks again

I love this place most are great at helping those of us who are new and small.
 
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