# Resizing Photos



## Lynnzora (Mar 9, 2009)

Ok I wanted to get some prints...  So I went to walmart.  I know, probably the last place that I should go.  My camera is 14 mp so the pictures are huge.  I thought that since I remember the digital photo kiosk in the store giving an option between different photo sizes that I didn't have to bother resizing my photos... that it would automatically do it for me.  The person working in photos agreed, saying that if I resized it myself in photoshop or something that it would mess up the photo quality.  After going on the machine I see that although it gives me size options it tends to shop off part of the photo still.

Even going through a professional lab (smug mug) it will chop off part of the picture if I don't resize it.  So obviously re-sizing is a must.  Now if I was to resize a photo this is what I would do:

Go into photoshop cs4... then to Image Size... Keeping the document size in inches...  I would resize the photo according to the size I want 8X10... 5X7...  OR am I going about it the wrong way... Should I be paying attention to the pixel dementions instead?  Would resizing it this way deminish the photo quality?  Is there a better way that I should be doing it?  Your help would be appreaciated.

Thanks Guys 

Lynn


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## Early (Mar 9, 2009)

Lynnzora said:


> Ok I wanted to get some prints...  So I went to walmart.  I know, probably the last place that I should go.  My camera is 14 mp so the pictures are huge.  I thought that since I remember the digital photo kiosk in the store giving an option between different photo sizes that I didn't have to bother resizing my photos... that it would automatically do it for me.  The person working in photos agreed, saying that if I resized it myself in photoshop or something that it would mess up the photo quality.  After going on the machine I see that although it gives me size options it tends to shop off part of the photo still.
> 
> Even going through a professional lab (smug mug) it will chop off part of the picture if I don't resize it.  So obviously re-sizing is a must.  Now if I was to resize a photo this is what I would do:
> 
> ...


I'm probably the wrong guy to answer this since it's been awhile since I printed, but I would use inches since that's what I grew up with.  In fact, the last time I printed, I used the software that came with the printer, and printed to the size of the paper without having to resize the file.


> Would resizing it this way deminish the photo quality?


Since you are lowering the resolution, I would say 'yes', and theoretically, even if you are copying the file using the same resolution, you are diminishing the quality.

Whatever you do, keep the original.


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## Lynnzora (Mar 9, 2009)

ok it makes since to adjust the inches to the size print you want.  But I don't know why I also got the feeling people also did it another way too... hummm  Well I won't know for sure if the quality is good enough until I actually do it.


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## rufus5150 (Mar 9, 2009)

Beyond a certain resolution, your prints aren't going to gain any quality (though the advice to keep the original is sound). That certain resolution is dependent on the printer. 300ppi is a rule of thumb for most printed material but 210-240 works for home printers. I use MPIX, they recommend 250 and claim no increase in quality beyond that.

That means for a 4x6 print, you won't lose any quality if your image is at least 1200x1800.

DSLR output files are a 2x3 aspect ratio (canon and nikon anyway, lots of P&S cameras are 3x4 these days). Any time you want to do a print that isn't in that ratio, unless you crop to the desired aspect ratio, you'll lose something or the picture will be distorted (by default, photoshop has the 'preserve aspect ratio' checked in the image size dialog, thus forcing you to preserve the ratio or uncheck the box).

My work flow makes a copy of the original, crops it to the aspect I want, then I resize it to fit the proper size for that ratio.


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## stsinner (Mar 9, 2009)

I thought I read that in CS3 Camera Raw, you can change sizes without affecting the quality.


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## rufus5150 (Mar 9, 2009)

You can crop in of ACRAW and you can (usually) bump it up to the next MP resolution (which is essentially a resize), but once you're pulled it into Photoshop proper, there's really not much going back to ACRAW (you can set it up to pull in tiff and jpeg into camera raw first). Any time you make something smaller, pixels will have to be modified. 

There's no mathmatical or logical way to do it otherwise.

Any cropping action so long as there's not a resizing action will not degrade the quality. Resizing in photoshop gives you the control over the method by which it resizes (which algorithm it applies, etc). If you turn in a 2400x3600 image and print it at 4x6 inches on a printer that uses 300ppi, you're trusting that software to do the resizing for you.


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## Lynnzora (Mar 9, 2009)

rufus5150 said:


> You can crop in of ACRAW and you can (usually) bump it up to the next MP resolution (which is essentially a resize), but once you're pulled it into Photoshop proper, there's really not much going back to ACRAW (you can set it up to pull in tiff and jpeg into camera raw first). Any time you make something smaller, pixels will have to be modified.
> 
> There's no mathmatical or logical way to do it otherwise.
> 
> Any cropping action so long as there's not a resizing action will not degrade the quality. Resizing in photoshop gives you the control over the method by which it resizes (which algorithm it applies, etc). If you turn in a 2400x3600 image and print it at 4x6 inches on a printer that uses 300ppi, you're trusting that software to do the resizing for you.


 
Ok according to photoshop my photo's resolution is 72 pixels/inch or (28.346 pixels/cm)...  And 2709X 4422 pixels...

So with those measurements what do you think I should take it down to.  Taking it down to 8X10 might be taking too much away.  Afterall when I try to print a photo via the kiosk or through smug mug, It gets most of the pic.  It justs chops off a little section.... hummm any suggestions?  Thanks so much for the comments so far.  I know I might sound redundant sometimes but it's just to be absolutely sure...


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## Mgw189 (Mar 9, 2009)

Lynnzora said:


> Ok according to photoshop my photo's resolution is 72 pixels/inch or (28.346 pixels/cm)...  And 2709X 4422 pixels...
> 
> So with those measurements what do you think I should take it down to.  Taking it down to 8X10 might be taking too much away.  Afterall when I try to print a photo via the kiosk or through smug mug, It gets most of the pic.  It justs chops off a little section.... hummm any suggestions?  Thanks so much for the comments so far.  I know I might sound redundant sometimes but it's just to be absolutely sure...



I use Walmart for prints for myself I use Iprintfromhome.com for prints for other people.  As far as printing at Walmart goes I usually resize to 8x10 with 300 DPI and then submit via the web for one hour photo.


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## rufus5150 (Mar 9, 2009)

You can set your resolution without affecting the overall pixel size (open up the image size dialog and and uncheck 'resample image', put in 300 or 250 or whatever the appropriate pixels/inch resolution is for the target printer -- next time you go into this dialog to actually resize, you'll need to turn that back on, though).

Apparently I wasn't clear though... you're taking a picture to them at a 4x6 ratio and they're looking to print an 8x10 ratio. You're going to lose some dimensions just based on basic geometry. Those will be lost whether you do it at your machine or you do it there. I prefer to have all of the control, however.

So if I were sitting and looking at an image that I was going to take to print and it was in a 2x3 aspect ratio (2709X 4422) and I were wanting to print an 8x10 photo, I would do the following:

0. (needs not saying, make a copy of the image)
1. Open Image Size
2. Uncheck the 'resample' check box
3. Put in 300 (or 250 or whatever) for the resolution
4. Click 'ok'
5. I would select the rectangular marquee tool
6. I would set it to fixed ratio of 4x5 (or 8x10, it doesn't really matter, as the ratio is consistent)
7. I would select the area I wanted to print. The 'fixed ratio' will ensure you have an 8x10 ratio. If you don't want to sacrifice any pixels, your shortest side must be at least 8 inches (if they aren't on, you should turn on rulers)
8. I would then crop (image->crop) the image
9. I would then open the image size dialog again 
10. recheck the 'resample' check box
11. If it's not exactly 8x10, go to the smallest side and put in '8' for inches

The fixed ratio in the image size dialog should keep it at approximately an 8x10 photo (there's sometimes a 1 pixel difference).

If your resolution is set for 300ppi, it will be 2400x3000 when you're done. 

If you needed to size up instead of size down, keep the algorithm on 'bicubic sharpener' (which it says it's best for reductions, it is, but it's also the best for enlargements, too), and you may need to do another minor sharpening pass aftewards.

There's a faster way to do this with the crop tool, but up until a year ago, I never worked outside of the screen media so I got used to the image dialog box and it's my go-to tool.

Basically it boils down to:

1. Get the resolution set correctly
2. Get the aspect ratio set correctly
3. Get the size set correctly

I handle these three tasks independent of one another and make my target image exactly what the printer needs so no editing at a kiosk (or through ROES, or on the website), and their machine makes absolutely no guesses about my intentions.


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## Lynnzora (Mar 9, 2009)

You're AWESOME for this! Thanks!!!


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## Lynnzora (Mar 11, 2009)

I have a question for you guys...  When you upload your pics to your online photo lab, do you have to resize at all?  Or does the lab (Zenfolio, smugmug...) do it for you?


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## mrodgers (Mar 11, 2009)

I only change the dpi and don't worry about the actual size. I also have never printed more than 8x10.

Just remember that you also have to change the ratio of the photo depending on what size you want. For example, most dSLR cameras shoot in 2:3 format which is the ratio of a 4x6, 8x10, 12x18, etc. If you want to print in a different ratio size, such as 8x10, you either have to crop to that size or the printer ends up cropping it themselves with less desirable results (they cut the head or feet off your little girl's portrait) or they print as is and it just prints with white bars on the sides.

Crop yourself so that you get the exact image you want instead of the printer just cropping directly in the middle.


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