Printing DPI What PPI?

[SamSlam023]

I am getting a large poster printed. The place I am getting it printed says the printer is 150dpi.

What PPI should I use for my image? I have tried to upload a image that is 150PPI and it gave me an error saying invalid file type. 72PPI and 144PPI worked though. Is there someway of working out the perfect PPI for this 150DPI printer or will 144ppi be good enough?

 

[Tom Mann]

Hi again, Sam -

Is this the same project that we discussed a week or two in this thread:

http://www.photoshopgurus.com/forum/photoshop-newbies/45063-upscaling-resolution-printing.html


Is it the same printer that you mentioned in post #3 of that thread, ie, Office Works?

If so, your latest experience (ie, 144 ppi works, but 150 doesn't) only reinforces my previous impression that that you may want to consider an alternative vendor. There should be do difference whatsoever in uploading the different ppi versions of that file.

Tom M

 

[SamSlam023]

Hey,

Yes this is the same project and from the same place. I understand that it would be better to go to a place that is more specialized in this area instead of just general office things but Office Works is the only place I can find that can print B0.

What PPI do you think would be best for the 150dpi printer? Should it be 150PPI or is dpi and ppi related differently?

Sam

 

[dv8_fx]

Large format prints are meant to viewed from a distance. I don't think you'ld be viewing a 55.7 x 39.4 inch print like you would a newspaper... lol . Impressive view tho.

Image resolutions are measured in DPI (Dots Per Inch) and PPI (Pixels Per Inch). There are differences between the two – DPI refers to a printed document, and the amount and spacing of the Cyan, Magenta, Yellow and Black dots, whereas PPI refers to the pixels on a screen.

Every printing bureau may have it's own preference. Since they say to create the image at 150 dpi, go for it.

 

[ALB68]

Large format prints are meant to viewed from a distance. I don't think you'ld be viewing a 55.7 x 39.4 inch print like you would a newspaper... lol . Impressive view tho.

Image resolutions are measured in DPI (Dots Per Inch) and PPI (Pixels Per Inch). There are differences between the two – DPI refers to a printed document, and the amount and spacing of the Cyan, Magenta, Yellow and Black dots, whereas PPI refers to the pixels on a screen.

Every printing bureau may have it's own preference. Since they say to create the image at 150 dpi, go for it.

Prey tell how does one create a 150 DPI Image in PS which uses PPI? What is a 150 dpi printer? Tom?

 

[dv8_fx]

There's no such thing as a 150 dpi printer, that's for sure. 30 years ago, probably (dot matrix printer) .

I'm not that versed with today's printers but most computer printers output at 85 dpi so your files need to be 170 dpi at 100%.150dpi is considered a standard in magazine print. This also means that your work should be set at twice the resolution of whatever your output device hence 300 dpi. What your printer suggested (150dpi) could well be the minimum acceptable size of your work image resolution.

For better production, 300dpi is good. But for your use, like I said - Large format prints are meant to be viewed from a distance - you can go with 150.

In PS terms, your work image document is at the size you require and set at the minimum 150ppi or standard norm of 300ppi (which has a side effect - one humongous huge file).

Why PPI? PPI refers to the pixels on your monitor screen.

 

[Tom Mann]

Unfortunately, I am out of town with only my little cell phone and can't fully participate in this thread. However, I will be back tomorrow night and try to help answer the questions.

However, in the intrim, I would comment that OP is dealing with a vendor who themselves has written Instructions which confuse dpi with ppi, and IMHO, this is what is prompting his questions. For example, anyone can look up the dots per inch rating of any modern photo-quality printer and verify for themselves that typical numbers are in the thousands of dots per inch. DPI is typically controlled by the printer driver and goes under names like photo-quality, high-quality, draft quality, etc. It is a completely separate quantity from ppi.

As has been already pointed out, there is no way the DPI of a modern print is going to be the 100 - 150 range. The print would look awful. However pixels per inch in this range are quite reasonable.

Also, one should not confuse either of these quantities with the line screen frequency used by commercial, large volume offset printing operations for which the factor of two multiplier mentioned above is applicable.

More tomorrow.

Tom M

 

[Tom Mann]

I should add that the OP's printer is not unique in failing to distinguish dpi from ppi. Most old-time printers used the terms dpi and line screen frequency for years before the advent of inkjet printers, for which one absolutely must distinguish these quantities.

What this means is that it becomes the task of the end user / customer (ie, us) to determine "which language" they are speaking. Realistically, the only way to do this is from the context of the interaction.

Obviously, the OP's preferred printer is using old, imprecise terminology even tho he will almost certainly print the OP's poster on a wide body inkjet for which one should be distinguishing between dpi and ppi because it obviously takes many dots of ink to render a full range of color in each pixel on such a device.

Maybe printers don't distinguish between dpi and ppi because they are trying not to confuse the customer, whereas, in actuality, they wind up confusing us even more :-( .

 

[dv8_fx]

I agree, Tom. Old time printers sometimes use old terminology which confuses even me at times.

So as an old work around to this, I'd do the work in PS either 150 or 300 ppi at full size. Even if the printer has to downsze the image to fit the material with a bleed, it will not affect the image quality. 50% downsize would be OK. Up-sizing would be a different matter. At +50%, image quality is affected most especially if your image has a lot of detail.

In a vector image , that wouldn't be a problem. But it seems the OP will be using an image found in another discussion thread - the Jurassic Park Guy if I'm not mistaken?


As an afterthought, .... SamSlam.... what did you mean when you said,,,,, " I have tried to upload a image that is 150PPI and it gave me an error saying invalid file type." ..... ? Upload here in the forum .... upload to printing office? For printing in your printer?

Regardless of resolution, the image should be OK..... clarify , please.....