300 dpi from 180?

[Kabz]

My company keeps telling me that in order to print, the resolution of the image MUST be 300 dpi.
I didn't understand because all photos that I have taken have always been 180 dpi or less.
Is there a way to convert up using my Digital Rebel?
Is it even POSSIBLE?
Does shooting in RAW make any difference at all as for as resolution (dpi) is concerned?
They want to make posters from the images taken so I'm just wondering if 180 dpi is fine or if it really does have to be 300 dpi to go through with printing.
Basically I'm really confused about the whole deal, so I hope someone can clear all of this up for me.
Thank you.

[robertwgross]

Please take the time to search this subject in this forum. It seems to pop up several times per month.

The typical Canon digital will place an arbitrary 180 dpi number on each RAW file. You are shooting RAW, aren't you?

That number doesn't mean a damned thing! No matter how you slice it, you still have the full number of megapixels.

Now, once you get the image into your editor, you can change the 180 and make it 300 or any other number.

Personally, I don't change it. I let my printer driver handle that.

---Bob Gross---

[Kabz]

you know I figured these things are covered.

thanks

[RoB_m]

the 300D can't make posters at 300dpi without resampling the image in photoshop or an enlarging program like genuine fractals. this essentially just adds in extra useless pixels and doesn't improve image quality.

how big of a poster are we talking about? the best way to enlarge in photoshop is to turn off resampling and enter the dimension you want. this keeps the same number of pixels in the image and only changes the ppi.

i've heard genuine fractals can make a billboard size print from a 10D image so i'd recommend using that.

[Kabz]

I wasn't shooting in RAW though......

[Kabz]

the 300D can't make posters at 300dpi without resampling the image in photoshop or an enlarging program like genuine fractals. this essentially just adds in extra useless pixels and doesn't improve image quality.

how big of a poster are we talking about? the best way to enlarge in photoshop is to turn off resampling and enter the dimension you want. this keeps the same number of pixels in the image and only changes the ppi.

i've heard genuine fractals can make a billboard size print from a 10D image so i'd recommend using that.

Genuine Fractals? could you explain this further?

[RoB_m]

doesn't really matter. although raw files are probably capable of being enlarged more because of the added exposure control you have during post prcessing. they have the same amount of pixels as the regular format shots.

[RoB_m]

the 300D can't make posters at 300dpi without resampling the image in photoshop or an enlarging program like genuine fractals. this essentially just adds in extra useless pixels and doesn't improve image quality.

how big of a poster are we talking about? the best way to enlarge in photoshop is to turn off resampling and enter the dimension you want. this keeps the same number of pixels in the image and only changes the ppi.

i've heard genuine fractals can make a billboard size print from a 10D image so i'd recommend using that.

Genuine Fractals? could you explain this further?

third party enlarging program. google is your friend.

[robertwgross]

Posters do not need to be printed at 300 dpi.

Anything less than a page size, then 300 dpi is a good goal.

Anything much larger, like a poster, is not viewed at such a close distance, so 300 dpi for a poster is overkill. For a poster, if you can get 200 dpi, that is generally pretty good.

---Bob Gross---

[Scottes]

Before you go spending money or possibly upsizing when it's not necessary...

As Bob said, the DPI means nothing. You can have a 3000x2000 image at 72 DPI or 300 DPI - it's still 3000 pixels by 2000 pixels. The DPI is only used when printing. 72 DPI will print at 42" x 28" and look like crap because the pixels will be large and spaced apart. The 300 DPI will print about 1/16th the size (10" x 6.7") but will look a hell of a lot sharper. Either way, it's the same picture and the same pixels.


What size is the image? And what size do you need to print it at? The print size times 300 will dictate the final pixel size, and this will tell you if you need to upsize the image or not.

We've recently been dicussing upsizing - a lot. Before you spend money on Genuine Fractals - though you can try it for free - read these topics: http://photography-on-the.net/forum/showthread.php?t=37151 and http://photography-on-the.net/forum/showthread.php?t=37558 and http://photography-on-the.net/forum/showthread.php?t=37747

You can do some excellent upsizing for free just spending a bit of time.

[Kabz]

much appreciated.
Thanks for taking the time guys....

Now I get to prove the company people wrong 8)