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Old Jun 8, 2006, 1:55 AM   #1
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I want to share pictures from a family gatherings and events. After editing in Photoshop Elements, what sizes and formats would be the most useful for people? I suspect that most recipients of these photos won't personally edit them or if they do it will probably be limited to whatever is possible via wizard. Files will be printed on a inkjet or at a service, e.g. Walgreens or Walmart.Here is the spec I'm thinking of, what do you think?

1. Provide two copies of files.

2. First set of copies in folder A: "Large files for high quality printing".

A. Keep all the pixels (6megapixels) and resize to 8 x 10 inches @ 250 dpi.

B. Universal lossless format such as tiff.
3. Second set of copies in folder B: "Small files for email, slide shows, and standard quality printing".


A. Resize 8 x 10 inch, 150 dpi.

B. Lossy format such as medium to high quality Jpeg.

Note: 150 dpi was selected as a compromise. 72 dpi is too low for high resolution (>XGA) monitors. 150 dpi allows zooming on screen and is adequate for basic quality prints. File size is a few 100k.
3. Possibly, a third folder of poor quality pictures that still might be of interest.

Questions:

1. Can I assume that slide show functions on most PCs will auto-size pictures?

2. Oftentimes, the preferred crop of the subject is not in a classic proportion, e.g. 8 x 10 inch. If the picturewill be placed in aframe, the result is an oddly proportioned border that could look unprofessional or otherwise distract from viewing. I have seen matting used to help in this situation, but it complicates the framing process. Must I constrain cropping to a classic proportion? Other options? What is recommended?

3. PSE4 reports that unmodified KM5D photos are 41.778 x 27.778 inches @ 72 dpi. Using PSE4's Image/Resize function (without resampling or cropping), if the long dimension is set to 10 inches, the result in a 10 x 6.649 inches @ 300.8 dpi. Is the difference between 250 dpi and 300 dpi meaningful on high quality printers (I don't yet own one).

4. Using PSE4's cropping function to a fixed picture size, e.g. 8 x 10 inches -- Even though this function may change the dpi, it does not resample correct? Therefore, any loss in quality is due to lower dpi and not resampling error, correct?

5. Is there a compressed format tiff that I can count on most software to open? Regular tiff's are almost 18 meg each, leaving room for only 38 or so on a CD.

Thanks in advance,

Scott
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Old Jun 8, 2006, 4:07 PM   #2
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The DPI count you see is just a number in the header. Changing it won't do a thing in the way most software interprets the image, provided you don't resample.

IOW, it doesn't mean a thing to most software.

The actual print density is dependent on the resolution of the image.

For example, if you want an 8x10" print at 300 dpi, you'd want to send the printer a 3000 x 2400 pixel image (7.2 Megapixels), which would require resampling to make a 6MP image larger. Personally, I wouldn't bother to upsample one, and most printer drivers do a pretty good job of resampling (if needed) anyway.

Around 240 pixels per inch is normally pretty decent quality on almost any printer. At 180 pixels per inch, you still get pretty good prints. Even 150 can look OK unless you're real close.

If I were going for higher quality prints, I'd probably resample to around 240 pixels per inch first to make sure I didn't get any pixelation (only if my image didn't have that much resolution at the desired print size, as I would not downsample one)..

10 inches x 300 pixels per inch = 3000 pixels
8 inches x 300 pixels per inch = 2400 pixels
Resoluton needed for 300 dpi print at 8x10 inches = 7.2 Megapixels (3000 x 2400 pixels).

10 inches x 240 pixels per inch = 2400 pixels
8 inches x 240 pixels per inch = 1920 pixels
Resolution needed for 240dpi print at 8x10" = 4.6 Megapixels (2400 x 1920 pixels).

10 inches x 180 pixels per inch = 1800 pixels
8 inches x 180 pixels per inch = 1440 pixels
Resolution needed for 180dpi print at 8x10" = 2.59 Megapixels

Your camera outputs an image size of 3008 x 2000 pixels (6 Megapixels)

After cropping to the correct ratio of width to height for an 8x10" print size, you'd end up with an image size of about 2500 x 2000 pixels (5 Megapixels).

That would give you an 8x10" print at 250dpi:
2500 pixels / 10 inches = 250
2000 pixels / 8 inches = 250

As for using .tiff files, I wouldn't. I always convert to jpeg for sending anywhere to print. Just use a higher quality setting for jpeg compression if you're considered about compression artifacts or loss of quality. At max jpeg quality, you won't be able to see any difference (since it will be using mostly lossless compression at maximum quality), and some software and printers won't support large tiff files.




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Old Jun 8, 2006, 4:30 PM   #3
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This may be useful, too:

http://www.photo.co.nz/faq/resolution.htm

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Old Jun 9, 2006, 9:55 PM   #4
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Jim,

Thanks for the help. I think I'm in pretty good shape on printing resolution now. Being able to use jpeg for high quality is a relief.

I'm still hoping for suggestions forlength x width proportions for picture files that I want to share. Since, I don't know what proportion someone might choice to print, e.g. 8x10", 4x6", etc., I'm thinking that I shouldn't crop tightly, to provide flexibility to later crop for the chosen picture size.

How do printing services handle a file with non-standard proportions, do they try to crop or just leave white space?


An article at Image Resource suggested that cropping shouldbe one of the steps in the workflow. My thought is that I can stillmake a conservative crop at the beginning, but willleave room to cropagain for various proportion pictures. Thentouch-up the image. An additional crop can be made later if and when a particular proportion is desired. Is there any downside to this approach?

Thanks again,

Scott

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Old Jun 10, 2006, 7:46 AM   #5
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How a printing service handles cropping depends on the service, and some will give you optons to do it more than one way.

Most will just crop in the center (equal crop on the sides that are too long for the print size needed). Some have the option of allowing extra border space.

Some even offer print sizes with no cropping, based on the size of the long edge you want (6", 7", etc.), printing the other end as long as needed (which makes it harder to get frames without you needing to do some custom matting).

Some print services have online crop tools, that let the users select the desired crop (shows on on screen crop box) when they order prints.

What I used to do is upload images to a printing service that had unlimited free album space. Then, just give family members a link to the album and let them order their own prints (or they can just view the images in the albums there).

The company I was using ( http://www.photoaccess.com ) merged with another company, and is now http://www.photoworks.com (and AFIAK, they still have free unlimited album space, since my albums are still there). When you order prints, you can specify crop type (center, etc.) with a print preview box showing the crop. I have not ordered from them since the merger, and they have switched from Fuji to Kodak paper. So, you'd have to try them out to see if quality is still good.

Users don't have access to the full size images (but, they use them for prints). Users can see slideshows, etc., there. They have a software package called PhotoStreamer that makes it easy to create albums on your local PC and upload the images to them.

I'd also upload the images to another service like http://www.pbase.com if they wanted to download the images and print them on their home printers.

Usually, I'd just upload images ready for 4x6" prints. But, for prints that I know they may want at 8x10" size, I have been known to precrop some (but, not all), with filenames indicating they are cropped for 8x10, with appropriate filenames for the crops (for example CindiWedding001_4_6, CindiWedding001_8_10)

I've used http://www.winkflash.com also. Their pricing is better (especially with .99 shipping). But, I was not as impressed with the way I had to try and get album links to others for ordering. It's easier with photoaccess (now photoworks), and users don't need to be logged in to view albums. Pros and Cons (price versus convenience).



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Old Jun 11, 2006, 8:43 AM   #6
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For cropping I use a program called http://ekot.dk/programmer/JPEGCrops/because I can crop to any size depending on the print I want and not let the photolab computer try to guess.
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