Resizing images in photoshop for printing.

I agree with D Fosse,

Resampling your images is to be avoided as far as possible.

It may, in some cases, be inevitable to reach the actual size you need but must certainly not be done multiple times 

if you want a 300 PPI*( image, as per the instructions you've received then you will need to set the resolution (in image size - with 'resample' unchecked) and see what physical dimensions your image can attain when PPI is set to 300. You are simply instructing imaging applications to use the pixels in a certain way, (so many for each inch printed) neither creating nor destroying pixels (which is what resampling does).

Maybe it comes out 11 x 16" and you want 12 x16. These 2 are different proportions so the image has to be cropped (or distorted) - then expanded (for which you would have to use resampling) to attain the desired size and proportion. 

Read some articles about image sizing and you'll eventually grasp it. It takes a bit to understand and is hard to explain without a one to one conversation using examples

I hope this helps

thanks
neil barstow, colourmanagement.net :: adobe forum volunteer
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Hi @D_Fosse & @NB__colourmanagement, Thank you so much for taking time to reply to my questions and answering them so patienly and in details, I appericiate it. 

I use a Sony A7iii for shooting my pictures and yes as suggested by both of you I have made sure to pump the DPI to 300 before sending it across to the printer. My main concern was how do I fit my photos with my original composition without loosing the details in the photo to cropping to fit a particular size.

@NB__colourmanagement What I am generally doing is opening a "new canvas" with size slightly bigger than the size I want to print, say for eg if I want to print a photo to size 12x16", I open a new canvas with slightly bigger size of 13x18" and then place my photo on that canvas and re-adjusting it with ctrl+T and then go to "Image" >> "Image Size" >>"Resolution">>300. Then I change the size by disconnecting the width and height and typing the desired size, in this case 12x16 inches and click "OK". Thats the process I follow and the last step is "Export as" go from there.

I want to know If am following the right method? thank you so much I appreciate you for all your time.

Cheers

Eleanor,]

you write:

"I want them to be printed as is without cropping, So i wanted to know how do i fit the photo for any given size with the original composition."

Of course you will need to set resolution correctly - you mentioned that your print service asks for 300ppi, so ideally you'll give them that.

I think that part of the process has been described well here already.

BUT your question makes me wonder if you're thinking about image propoertion.

IF the desired print format differs in proportions to your original, then to keep the proportions of your original you'll need to either crop to the right proportion [losing some of the original image] or to print with an uneven white border - just set one image edge to fit and allow the other to be set automatically by the "restrain proportions" feature of  image size [the 2 dimensions are linked and a symbol present to show that].

No need to make white borders in a Photoshop image by adding to the "canvas"- the correctly sized image can be placed within the white paper by the printer, leaving a border.

I hope this helps

thanks
neil barstow, colourmanagement.net :: adobe forum volunteer
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What's the SIZE of the output you desire AT a DPI value for the print? You want a 8x10@300DPI, you need 2400x3000 pixels and that's what you'll ask for in the Image Size dialog for interpolation from the original image. Then if you want a border, just use Canvas Size and add that next. 

PPI has absolutely no role in quality per se. It is simply a resolution tag. The tag could be 72PPI or 180PPI but it doesn't have an inherent meaning, only what you could produce with the number of pixels you have at your disposal. Work with pixels! For example, let us say you have 1000x1000 pixels to keep the math simple. And to simplify this further, let's only consider the horizontal axis. If you have 1000 pixels and divide that by 72, that is, you provide 72 pixels per inch, you could end up with 13.8 inches using that division (1000/72=13.8). Let's now say you divide up your 1000 pixels using 180 instead. 1000/180=5.5. In both cases, you had 1000 total pixels. The document itself doesn't have a size, other than what space it takes up on your hard drive. The sizes above are examples of what could be produced if you divided up the total number of pixels you have, with some number of which is just a tag within the document. In Photoshop, if you use the Image Size dialog, turn resample OFF (do not allow it to create more or remove pixels), you can enter any value, 72, 180, 1000 into the resolution field and the resulting size is calculated for you. But you haven’t changed the document or the data at all. You just changed a theoretical 'size' if you output your 1000 pixels using that resolution. So again, it's meaningless until you output the data. At that point, lets say you print the image, you can decide how big you wish it to appear and/or how many pixels you want to devote to the output. You have 1000 pixels and someone tells you that you must use 300DPI (which isn't true but that's a different story). 1000/300 would produce a 3.3 inch print. You want a bigger print? Lower the DPI (within reason). You set the DPI for output to use 180 of your pixels to produce 180DPI? You get a 5.5 inch print (1000/180=5.5).