Increasing print size of cr2 file with photoshop

lida

Hi folks,
Need a little help. Am very new to photoshop and high quality large prints. Have three cr2 images, taken with canon EOS 20D. Average size of each file 8mb. Need to know max size they would print out as they are now and would also love to know if I resize them in photoshop, what is the biggest print size I could get without losing high quality and now that I'm pushing it, could the genius who replies to this walk me through how i do that in photoshop...? How do you work it out ? Need to get them at 24 inches by 32 inches...if possible

Fajitas!

Hmmm, you won't get them at that size without the quality going down...

This isn't gospel, but I'll tell you what I think I know

8mp will generally give you A3 without any loss of quality...possibly A2 (16.55 x 23.40 inches) with a bit of a loss, but for A1, you'd need to be standing a metre or a bit more back from the image to not see the loss of detail.

Now...what you're after to get it up to that is called Interpolation.

You can buy interpolation programs off the internet, that do the job very well, but these can be fairly costly.

The easiest way to do it, is open photoshop, go to image, image size, and select inches, and resize from there. bearing in mind that you're gonna have to increase the amount of pixels per inch too. I'd say go with 300 ppi, the average for printers is 240.

paudie

Well isn't the thing with big prints that you will be viewing from far away anyway?

So it'll still look the same? Who looks at poster from closer than a metre?

Fajitas!

Not nessicarily. Sometimes you'll want clarity accross the whole image. Understandibly I guess!

lida

Fajitas, you're a little egg! Will follow your instructions and hopefully it'll be grand. And yes, clarity throughout the image would be great as they are going into someone's office which I'm sure will allow folks to stand a metre or unfortunately, a little closer than a metre to them....

Any opinion on foto.com for canvas printing quality???

Anyway, thanks for your help

Valentia

If people haven't heard of this trick yet, it works. Increase the photo size in PS by 10% with bicubic interpolation turned on. This can be done numerous times to get the size you want. It will give really big print sizes with very little loss of quality. None of the experts seem to know for sure why this works but it does. Scott Kelby shows how to do it in "PS Tricks & Tips" but better still you can download an action here that will save you the trouble having to select the routines every time. Just run the action as many times as you need. There are some additional actions thrown in too. The "Supersize Upsize" is the one you need.

I have done this many times. It's amazing.

Fajitas!

Wow...must remember that Dan!

Espec when I get the 5D...

Btw Lida, remember to show us/let us know how it turns out! G'luck!

lida

Valentia, Fajitas

I'm very sorry but can I just run this by you both and ask you to confirm I'm doing this correctly as I have downloaded those actions via your link Valentia (Thank you very very very much!)
I open the raw cr2 in PS. Am I best off to changing file format from cr2 to tiff or jpeg...does it make a difference?

From there, rather than resizing through image size option, I'm now using my action palette to play these 10% increments...now folks, this is where i must apologise.....is it a case that my original image when opened initially is let's say 4992*3328 in size at 240 pixels per inch. And if I use the stepwise upsize or 100% upsize to increase 10% (Valentia, I could find the Supersize Upsize option you mentioned so I presume it is one of these?), in lay man's terms, this will give a 10% increase in width & height so no longer is the image 20.8 *13.87 inches in size, it is now 22.8 * 15.26 inches in size....is this the correct way to calculate the size increments?
And although the image is at 240 pixels per inch originally, where do i then increase it to 300 pixels poer inch or is there a need now with this new high quality enlarging method Valentia has lended?

Where do I find out how many dpi the original image contains and am i best off using the new downloaded actions to increase this to 300dpi....is it really as simple as clicking on that particular play action once?

I can't apologise enough for the heartbreaking questions but I am very new to the whole world of photoshop but am enjoying the learning game...so thanks if you can help me further and if you can't, I appreciate all you have both given already...cheers

lida

Folks, Iknow Im poushing it now but whats the difference between 8 bit and 16 bit? IMages are in 8 bit....will the printed result be different/better/worse if i changed to 16bit?
Cheers

Valentia

Am I best off to changing file format from cr2 to tiff or jpeg...does it make a difference?

Once you are happy that you have the photo the way you want it you are fine using jpeg. Tiff will lead to gigantic filesizes.

From there, rather than resizing through image size option, I'm now using my action palette to play these 10% increments...now folks, this is where i must apologise.....is it a case that my original image when opened initially is let's say 4992*3328 in size at 240 pixels per inch. And if I use the stepwise upsize or 100% upsize to increase 10% (Valentia, I could find the Supersize Upsize option you mentioned so I presume it is one of these?), in lay man's terms, this will give a 10% increase in width & height so no longer is the image 20.8 *13.87 inches in size, it is now 22.8 * 15.26 inches in size....is this the correct way to calculate the size increments?

My eyesight is sh1t. Sorry it's "stepsize upsize". This one will give a very good final pic, quality wise. In the "View" menu make sure "rulers" is ticked. Select the magnifying glass and start your resizing. At any time right click on the pic and select "Fit on Screen" or press the "Fit on screen" button at the top. This will tell you the size. If you want inches make sure measurements are set to inches in the preferences. Your thinking is correct. Experement by making any pic 10" wide. then do the Stepsize action once. You will see that the width has gone up to 11".

Valentia

lida wrote:

Folks, Iknow Im poushing it now but whats the difference between 8 bit and 16 bit? IMages are in 8 bit....will the printed result be different/better/worse if i changed to 16bit?
Cheers

Mostly, your images need to be 8 bit for printing. 16 bit is useful if you are editing a tiff at that resolution. Jpegs don't do 16 bit. I convert from RAW sometimes to 16 bit Tiff. Editing in 16 bit preserves more detail which is very difficult, or impossible, to see on a monitor screen.When finished editing I save one 16bit tiff and a jpeg. I only do this for very special pics so I don't obviously have to do it very often

Roen

Your eyesight is even worse than you thought Valentia, it's Stepwise Upsize, not Stepsize Upsize

Valentia

Where do I find out how many dpi the original image contains and am i best off using the new downloaded actions to increase this to 300dpi....is it really as simple as clicking on that particular play action once?

Sorry, missed this. The dpi is changed in the "Image size" command. Just change it to whatever you want. You will notice that the size of tour image changes. A 2100 x 1400 @300 dpi will give a print size of 7" x 5".

BTW 300 dpi isn't really necessary. 150 is usually enough to not see any difference.

Valentia

Roen wrote:

Your eyesight is even worse than you thought Valentia, it's Stepwise Upsize, not Stepsize Upsize

You hoor you That's twice you got me in a week. You should hire yourself out as a spell checker!! :rolleyes:

Roen

Heheh, well I'm good for something, I wouldn't mind but my own spelling can be atrocious at times

Valentia

And I thought I was sorted with Firefox 2's new spell checker!

lida

Valentia,
I spent hours yesterday messing around in photoshop with that new action palette...and i just have a few questions...
Do i do all resizing/redoing dpi etc before or after I save the original cr2 file as a jpeg?

And secondly, when i go into image size in the stepwise upsize, there's an option there to input my desired print size rather than running the action 5 times or so...i did both...would there be a difference or will the result of my one input be the same as running it 5 times so it comes close to my desired size?

Also, using the action 240dpi to 300dpi...will it have much of an effect on the printed file? I did that too....
Once again, thanks to you and all who have helped...sorry about your eyesight!:D