Image resolution in prepress vs. rip

[JPR-5690]

When enlarging files and maintaining resolution, is it best to do it with say, Photoshop, before moving the file into the RIP?

Or during the RIP printing process (i.e. while the file itself might be 100dpi I could print at 600dpi)?

In this particular case I have a bunch of 8x10in's @ 300dpi that need to be enlarged to 3x4ft.
They're printing on relatively rough fabric so it's not like the resolution has to be museum quality, but I'd like to be dealing with files correctly and not wasting time in prepress if it's not necessary.

Unfortunately I can't just ask the client for higher res images (at least in this situation).

 

[myront]

export for print at 150dpi with LZW compression. Any more is overkill unless print is under 15inches or so and will be "in your face".

 

[Solventinkjet]

No matter what you do, your final DPI is going to be about 66 due to the enlargement factor being about 4.5. That's pretty low so it's probably going to look pixelated. You could enlarge in Photoshop and make sure the "Resample image" option is selected and choose the "Bicubic Smoother" option which will attempt to reduce the look of the pixelization but it's not great.

 

[JPR-5690]

No matter what you do, your final DPI is going to be about 66 due to the enlargement factor being about 4.5. That's pretty low so it's probably going to look pixelated. You could enlarge in Photoshop and make sure the "Resample image" option is selected and choose the "Bicubic Smoother" option which will attempt reduce the look of the pixelization but it's not great.

That's what I usually do, and luckily Photoshop has gotten pretty good at enlarging images without too much tonal distortion.
I just didn't want to take the time to do that with all these images and then find out there was a much easier way to be going about things.

 

[Bobby H]

I try to stick with vector-based objects whenever possible for large format printing, which leads to EPS or PDF use for printing. If something is generated from scratch within Photoshop I'll create it with a target PPI resolution in mind. 72ppi is usually good enough for raster-based graphics on vehicle wraps. But a poster or something else people will view closely might be better at 120ppi or 150ppi. You get what you get with photographs. It's great if you can get an original size image equivalent to what the camera captured (and really great if it's a lossless Camera RAW file). Any up-rezzing of high quality images is less noticeable.

 

[ColorCrest]

not wasting time in prepress if it's not necessary.

Print one image using both methods; photoshop method and the RIP method. Then you'll know how your files appear.

IMO, you are most likely to be wasting time unless you just send them to RIP in this instance. That's my short answer for now. Otherwise, original pixel quality, your expertise at upsampling, and viewing distance play a crucial part for more qualified answer.

 

[greysquirrel]

minimum 100DPI at final size....I prefer 150.

 

[thomlov]

Adobe Rip engine (Onyx Thrive and alike) as anti-aliasing/smoothing when enlarging images, to stop them from being pixelated. It's a setting.
But you have more control over it if enlarging in photoshop, and you can see the result without printing it.