Resizing for printing

[Lesley Bray]

I would like to print a section of my image as a 20x10inch photo.
I imagined if I cropped to a ratio of 10:5 this would be sufficient.
The lady at the printing shop says yes but also save the image as a 20x10inch at 300ppi.
This is the part that does my head in.
Do I select Bicubic Smoother?
Do I select Resample Image?
Do I select Constrain Proportions?
Thank you for your help - I have never bothered printing my images before.
Lesley

[ricktas]

Firstly do not upsize it in one go. Try going up in steps. So upsize it to say 10 x 5, then repeat to 15 x 7.5 then go to 20 x 10. There is plenty of evidence that doing it in stages results in a better upscale than doing one single jump.

If you want really good results try using photoshop plugin 'genuine fractals' (some older versions are kicking around the net as a free download, or under its new name Perfect Resize : http://www.ononesoftware.com/products/perfect-resize/

[Lesley Bray]

Thank you Ricktas - great feedback. Off to find a down load now.
Lesley

[ameerat42]

I would like to print a section of my image as a 20x10inch photo.
I imagined if I cropped to a ratio of 10:5 this would be sufficient.
The lady at the printing shop says yes but also save the image as a 20x10inch at 300ppi.
This is the part that does my head in.
Do I select Bicubic Smoother?
Do I select Resample Image?
Do I select Constrain Proportions?
Thank you for your help - I have never bothered printing my images before.
Lesley

10:5 is 2:1
If you are going to significantly increase the actual size of the image then you will need to Resample the image and Constrain proportions.
But what is the size of your image, for example, 5184 x 3456 pixels for the 18 MPx Canons?
Even if you crop down to about half the original image the image resolution should be able to handle (well, almost) the size you mention.

A hint: Look up the terms in Photoshop Help. It is quite clear and comprehensive. If you have not done this before, it will be a bit like trying to drive a big truck.

Before trying answering your Qs, do a bit of testing. Crop out the section you want to print. Then, in one hit, set the Image size parameters to achieve what the shop requires, ie, 20x10 inch and 300dpi (they said ppi?? Curious.) How does the image look on your screen when you set to view it at "Print Size"? Are there any obvious enlargement artifacts? If it looks OK then that should do it. If it looks blotchy, then certainly do as Rick said: do some enlargements in stages.

Now to your Qs...
If you are using the straight Photoshop features and not the ones Rick mentioned, then...
Enlarging by stages, use just straight Bicubic.
YES to both Resample image - you are trying to put pixels in where they are not, - and Constrain Proportions. (If you don't it just means you have the option of distorting the image.)

A final note: If straight Bicubic looks a bit jagged in the result, try the Smoother option. You may then have to apply some mild Smart Sharpening to the result. I would not use Bicubic Sharper for enlarging images, but for reducing their size.

Well, if you are confused that's a good sign.
Am.

[Lesley Bray]

I am totally indebted to you both for this help - excellent advice and more than I ever expected. I have downloaded the Genuine Fractals and processed my image with good results - I am very happy right now (was a different story an hour ago). I feel that I have so much to learn !!!!! Am now going to work through your advice Am and compare to Genuine Fractals results. Yes the print place did say ppi.
Thank you so much
Lesley

[Damo77]

Firstly do not upsize it in one go. Try going up in steps. So upsize it to say 10 x 5, then repeat to 15 x 7.5 then go to 20 x 10. There is plenty of evidence that doing it in stages results in a better upscale than doing one single jump.
WTH? There was plenty of evidence that CRT monitors were superior, too, but that's long been superseded. So it is with the staged upsampling.

[Damo77]

(they said ppi?? Curious.)
Why curious?? PPI is the correct term.

[ameerat42]

On reflection, less curious. Some transient thought at the time, and editorially too late to alter. :(

[ricktas]

WTH? There was plenty of evidence that CRT monitors were superior, too, but that's long been superseded. So it is with the staged upsampling.

So how about offering something productive to the thread?

[Damo77]

Indeed I will.

For starters, 20" wide is no particular challenge for modern cameras. Lesley may not need to upsample much at all.

Honestly, the best way is just to set the Crop Tool to 20x10 @ whatever resolution the lab recommends (often 300, but not always) and crop. End of story. Then sharpen, save and send.

However, to be slightly more scientific about it, I would suggest cropping to 20x10 with the resolution left blank. Then duplicate the document (so there's two on screen) and upsampling them both to 300ppi, one with Bicubic, and one with Bicubic Smoother. Then compare the results and choose the best one. Then sharpen, etc.

[Lesley Bray]

Update - I downloaded Genuine Fractals - and used that software for upsizing to 20x10 - checked it out in CS3 at print size - when I was happy with it I sent to printers.
Picked it up yesterday from the printers and very hesitantly opened the parcel - I was prepared for a mediocre result. I am happy to say it turned out fantastic - and I am so very very happy with my photo. Now to have it framed. Thank you everyone for your assistance. It seems to me I have so much to learn about photography, even printing is a challenge.
Lesley