Scanning in 24"X18" poster

[Philippine Mango]

Yea I'm trying to scan in a poster of a porche and was wondering how many DPI I should scan in the poster and was also wondering if scanning in at a too high of DPI will acutually ruin the quality of the poster.

 

[GoingUp]

you need to account for the fact that its offset printed.

I used to scan in lots of large maps. Keep in mind that the filesize might be 10-50 megs but once you open it you can take up to 2 gigs of memory.

Just so you know.

 

[Eli]

Isn't 300dpi considered optimal?

So you'd need a 38.8MP image.. If you were printing a 24x18 digital picture print, at least.

:Q

 

[Philippine Mango]

Yea I scanned it in at 720DPI because 1200DPI seem too much for me. The file currently is about 1.25GB (has like 7 layers because I had to scan only parts of the poster at a time). 720DPI too much? I don't know if it damaged the quality of the pictures or not but when I zoom in photoshop, I can see 6 dots (each colored) and that is what comprises of the image. Would 300DPI let me do this?

 

[Eli]

Originally posted by: Philippine Mango
Yea I scanned it in at 720DPI because 1200DPI seem too much for me. The file currently is about 1.25GB (has like 7 layers because I had to scan only parts of the poster at a time). 720DPI too much? I don't know if it damaged the quality of the pictures or not but when I zoom in photoshop, I can see 6 dots (each colored) and that is what comprises of the image. Would 300DPI let me do this?

LOL, I don't really know what I'm talking about, so take everything I say with a grain of salt.

I'm failing to understand how composing an image of more pixels is going to degrade it's quality, though.

Is it different for scanning than printing pictures? Cuz that's the only DPI I'm familiar with.

 

[Eli]

Here's an idea.. scan it at everything from 300 to 1200DPI and compare them all.

 

[gutharius]

Originally posted by: Philippine Mango
Yea I scanned it in at 720DPI because 1200DPI seem too much for me. The file currently is about 1.25GB (has like 7 layers because I had to scan only parts of the poster at a time). 720DPI too much? I don't know if it damaged the quality of the pictures or not but when I zoom in photoshop, I can see 6 dots (each colored) and that is what comprises of the image. Would 300DPI let me do this?

Phillip,

I have tried scanning printed images before and they always turn out like crap because of the way they are printed. Best guess is to scale it down by 50 percent to get photoshop to merge dots. Of course this will make the pic of the porche have the original size of the poster. that is the best that i have been able to do.

 

[gutharius]

OH BTW DPI is used for print out quality, you usally want 600 for print outs. anything more is overkill unless you are using a commercial quality printer that can handle a higher dpi.

 

[Eli]

Originally posted by: gutharius
OH BTW DPI is used for print out quality, you usally want 600 for print outs. anything more is overkill unless you are using a commercial quality printer that can handle a higher dpi.

Ah. So is it 600 best, 300 minimum?

 

[gutharius]

300 for smaller printouts. 600 for larger ones. really it depends on the device you are going to use to print the image out and what it can handle as far as dpi goes.

 

[Aquaman]

With my 600 magazine scanning project (search for "scan" to find the thread) I am doing 150dpi and it's not bad print quality. I did a test with 150 vs 300 dpi and the difference was not too bad (althought it's not on a pro printer...... just a Canon S600 ink jet).

Just my experience.

Cheers,
Aquaman

 

[yhelothar]

Print, then 300dpi, no print, 150 to 75. Your monitor is usually only around 110dpi, so 110dpi would be about lifesize.