Scaling an Image

[SAR.Summerlin]

Ok so don't chew me out this is a rookie question I am sure but the boss wants a easy to understand explanation. And before you say search the forums or Google I have spent the last 1.5 hrs doing just that.

So here is the question. We are looking a buying an image that is 300dpi and 26.9" x 14.3" if we scale this up to 60"x 24" (will be cropped to get this) what would the new dpi be and how would it look.

Is there a calculation formula for figuring this out I have 11 images I will need to do this with all varying sizes?

for your help Alex

 

[J Hill Designs]

depends on how much of it is cropped...

but in laymans terms, 26.9" @ 300dpi would be 53.8" @ 150dpi (notice a pattern?)

 

[Gino]

You're barely doubling before cropping, so you shouldn't have any problems.

 

[signswi]

26.9/60 = .4483, * 300 = 134.49 dpi

 

[Matt-Tastic]

OK. Basic math lesson for today:

DPI = Dots per inch

If you have 300 dots per inch on a 26.9 inch image, you have 8070 dots (300x26.9=8070)
If you have 300 dots per inch on a 14.3 inch image, you have 4290 dots (300x14.3=4290)

If the recommended printing resolution is 100 dpi (my basic minimum), you can print this image as large as 80.7 inches by 42.9 inches with acceptable quality (8070/100 x 4290/100). Anything smaller than those figures should be acceptable image resolution for sign purposes. If it is short view ("Smelling distance"), you may not want much larger than the native size (300dpi is typically max useful resolution).

These are all general recommendations, and each file is different based on compression and file type. But that should get you going.

Also, your file resolution and your printer resolution are not the same thing.

 

[SAR.Summerlin]

Thanks everyone very helpful now to get my boss to understand.