Watching Jeff and Michael in "from Camera to Print", and reading "Real World Camera Raw CS3" (nice job that, Jeff), I think they've made a good case not to resample when sizing an image for printing. Let it stay at "native" resolution while resizing and let the final output resolution fall where it may; choose the nearest resolution and intended surface gloss when selecting PhotoKit output sharpening; and print.

Much of my printing is done via ImagePrint. My understanding (maybe this is a re-RTFM moment) is that ImagePrint up- or down-rezzes to 360ppi for output.

So if resampling is going to take place, would it be better to do so in Photoshop using whichever version of Bicubic is appropriate to the direction one is re-rezzing; or let IP do it on its own?

Forgive me if I've missed the obvious somewhere...

I asked recently a similar question, so perhaps you could find the answer in this thread:

http://luminous-landscape.com/forum/index....42&#entry154042

I think an argument can be made not to resize and increase resolution prior to sending the file to print or RIP.
But it would depend on what type of printer you are using. Ink Jet printer ppi requirements vary by brand, Web Press does not need the extra resolution.

I convert my RAW files in ACR 4.3 to 600ppi prophoto 16 bit, but do not change the dimensions of the file. I then convert the files to a custom icc profile for my printer and print via 16 bit Photoshop plug-in to a Canon iPF5000 printer. The printer prints best at 600ppi, but I allow the plug-in to resize the dimensions of the image to my desired paper size. This seems to produce better prints than trying to resize and increase resolution prior to sending the image to the printer plug-in.

Slobodan, thanks for the link. I missed that thread somehow when I searched.

I've posted a query there about whether Michael's information--just send to printer at native resolution--holds true when printing thru ImagePrint.

IOW, does IP use the native printer drivers--which Michael indicates from his discussions with those in the know do the best job of interpolation between 180-480ppi--or does it use its own drivers?

Thanks for everyone's input.

Mike

Imageprint completely replaces the native printer drivers.

If you do not change the image dimensions, you can't be at 600 PPI, I suppose. What is your image width and height in pixels? What is your printer format?

Yes, but printer PPI are fixed from the manufacturer to best fit the hardware. So I think:
1- Imageprint works at the same PPI value as printer driver
2- Imageprint works at different PPI value, in such a case I think the result can't be better

Jacopo

For example, I open a raw file in ACR 4.3 with ProPhoto 16 bit and 600ppi. I am already changing the native resolution of the raw file. The resulting image opened in Photoshop is 4000x3000 pixels, 68.7 mb.
It is roughly 6.7" x 5". If I want to make a 17" x 22" print of this image, I would not resize in Photoshop, but instead export the image to the Canon iPF5000 via the 16 bit Photohop Plug-In. This acts as a RIP and by passes the normal printer driver. I allow the plug-in to resize the image to the paper size, since I have already increased the file ppi to 600 which is the printer's native resolution. This seems to result in a better image than both resizing and up-rezzing, which results in a ridiculously large file size.

You are sending an image 4000x3000 to print at 22x17. The PPI value is 176,5 and the image must be cropped (117 pixel)

22 = 3883/176.5 (4000 - 3883 = 117)
17 = 3000/176.5

A better PPI value is 300 PPI (an half of the printer resolution). that means 6600x5100, same crop.

Photoshop is not a top resampler.

Jacopo

I think you are misunderstanding me. I am not resampling in Photoshop, that is the point I was trying to make. I just used 17" x 22" as an example, I know the proportions are not exact.

The RAW file is 3000x4000 pixels @ 72 ppi, with RAW processor ACR 4.3, I select ProPhoto 16 bit and 600ppi. Color adjustment and any sharpening is done is Photoshop and the image is EXPORTED from Photoshop to the Canon proprietary 16 bit printer plug-in where it is resized to fit the paper.

You haven't 600 PPI. The PPI value doesn't make sense until you fix the output format. An image has a width x height pixels. But until you lay down it on some device it has no physical size, as a pixel has no physical siza.

I understood that you do not resample. My suggestion is to do it with a good algorithm.

Jacopo