Big Print

[OmlessWanderer]

You need to save it to an sRGB Jpeg, becuase that's what it will eventually get converted to anyway at some point in the printing process.

Not true... It's dependent on by who and how the image is being processed. Many digital print systems, especially archival quality, use CMYK tones. Others, like a Konica machine(If you see one of these big blue machines, run) I used while developing at a 1-hr place could open any major image type and using it's built in flatbed scanner created tiffs.

 

[Sw1tchFX]

My school requests us to use Jpegs for printing on their giant printers simply becuase if you do a low compression jpeg, you don't loose any visible detail unless you start manipulating it again, and their much smaller/easier to work with. Also, becuase the jpegs are so small in comparison to TIFF's, they can have the printer multitask more files.

 

[EOS_JD]

As said above it's for you to choose what file type you send based on the information your lab gives you. If you have a Mac (which I guess you have), I'd send the Mac Tif because that's what they asked for. I'd probably save as aRGB for the higher colour gamut but check the colour space they'd prefer. It is unlikely the file will be converted by the lab to jpg if they have requested a tif.

I think the reference that the file would be converted is because most of us just send jpg images to the labs because that's what most ask for and because file sizes are many times smaller or the same quality of document.

Most convert RAW images to Tif or PSD then once the edits are done the file is either saved as a tif/psd or (more likely for most) as a jpg file for printing. Colour space is also down to your lab. Most like sGB but better labs will accept adobe RGB which is better because it has a wider colour gamut than sRGB.

There's nothing to be confused about. Follow the advice of your lab.

To clarify - the file is unlikely to be converted to jpg if the lab request a tif file and you supply this. It's just that somewhere down the line most of us convert to jpg for printing mainly because quality is near identical and the files are many times smaller. Regards quality, a jpg saved at maximum quality from a tif file is unlikely to show any loss in the quality of print.

Further to answer the OPs question, this is how I'd save for a 20x30" document.

I'd be looking for a file of approximately 5400 pixels x 3600 pixels (this will print a 20x30 at 180ppi). You will probably need to upsize your image slightly to get to this size but your lab may be able to do the upscaling from your edited file.

180ppi is fine for an image this size. I routinely print at 180ppi for my 19x13s from my Epson R2400 and they look stunning. In fact you could probably print a 20x30 at 150ppi and get great qiuality.

Save the image as a tif/jpg

 

[Christie Photo]

To clarify - the file is unlikely to be converted to jpg...

THAT'S what I was driving at. I just wanted to clear up that it is NOT an inherent part of the printing process to convert all files to JPG as was stated.

Thanks.

Pete