Upsizing In PS For Printing

[@dave]

I'm about to start using a photo lab (local to me) for printing up some of my images. The use a Frontier 570 printer for their standard work (up to 18 x 12) and print on Fujicolour Crystal Archive Supreme. This is very much a push the button & print service however several pro & serious amateurs local to me rate the service.

They need images to be 305 dpi. Say I have an image of 3200x2400 pixels this, would only give me a print of 10.49 x 7.86 inches. If I wanted a 16 x 12 inch print I would need to interpolate in PS to that size (i.e. to 4880 x 3660 pixels)

1st question is ..... how far can you go, using PS to upsize, before you start loosing (discernible) quality?

2nd question is ..... they say the images must be in JPEG saved at a quality of 8 - 10. Is this normal? I kinda expected they would ask for hi-res TIFF files? Or perhaps this is a minimum?

Any advice gratefully received

Cheers, Dave B.

[Bindii]

I know that I know the answer to this Dave.... but for the life of me I can't get it together tonight..

its late... *sigh*..

but I've moved it to the right area of the forum for you though... I am sure that someone will be along soon enough to answer your question for ya...

:)

[BarryM]

all i do is open the image in ps set a crop to my pic size i require i.e. 16x 12 at 300 dpi then do any work to it save as jpg and send to print at daves lab here quality has been great no issues at all

[Chris Hawkins]

Dave,

I don?t know how far one can go with changing image size in PS, but 18 x 12 is certainly not an issue. I print sharp images at 19 x 13 (A3+) without issue. Suggest you commission 2 or 3 shots where you push the boundaries and view the results for yourself. Scott Kelby opines that PS interpolation is as capable as Genuine Fractals. As for the 2nd question, the use of JPEG is quite common in commercial photo printing and I use JPEG for printing on my B9180 ? I would be surprised if there was any discernable difference between an 80-100% (beware there are multiple scales ? PS uses 1-12 not 1 ? 10) JPEG and it?s TIFF relation.

Cheers

Chris

[lostmysnorkel]

Yup, I'd resize it in PS - your not incresing to a great extent so shouldn't need any special software for it.

Select the crop tool and set the boxes to the dimensions you want - 16 in / 12 in / 305 dpi.

Crop the image, sharpen if needed, and 'Save As......' rename the file so you keep your original intact.

I would still save it at maximum '12' compression in PS - as has been mentioned, some software use different scales.

If still unsure, give the lab a call and ask them....they';ll be willing to help I'm sure

[simonkit]

I upsize to 30 x 20 inches & add a little sharpening - printed images are excellent

From CS2 onwards the "image resize" function in Photoshop has been constantly improved

simon

[Wadey]

The interpolation algorithms in CS2 and CS3 are excellent.

You can easily upsize a decent quality image by as much as 400%, before you really start to see any major degradation.

However, if you are going to upsize to any large degree, don't use the crop tool.
The tool is fine for minor re-sizing projects, but it doesn't use the bicubic algorithms within Photoshop, so it doesn't do as good a job.

For large size changes, go to "Image Size" and change the numbers in the boxes to get the size of print you are after.
Make sure "Resample" is checked, and select "Bicubic Sharper" from the drop down menu.

You'll get a better result that way.

By the way, if you are downsizing an image significantly, do the same, but use the "Bicubic Smoother" Option.

Also, do not sharpen the image before upsizing, do it after you are happy with the new image size.