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Old Sep 1, 2004, 11:14 PM   #1
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I have the i9900 and it only does 13 by 19's so I was looking for some reccomendations on how to split a picture in half or perhaps in quarters, print each section out individually then frame them all in an area for a nice effect. I have photoshop just looking for some advice on this. my camera is 5mp G5 so i'm sure the quality is high enough for this.




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Old Sep 1, 2004, 11:30 PM   #2
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If using Photoshop, look into the help files for "Slicing, or Slices." I know that Macromedias Fireworks does this & I'm pretty sure Photoshop has the same function. It basically cuts an image into smaller pieces so you can arrainge them on a Web page for much faster loading. I'm pretty sure that you could use the same function for prints, etc.
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Old Sep 2, 2004, 2:14 AM   #3
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timothy015 wrote:
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I have the i9900 and it only does 13 by 19's so I was looking for some reccomendations on how to split a picture in half or perhaps in quarters, print each section out individually then frame them all in an area for a nice effect. I have photoshop just looking for some advice on this. my camera is 5mp G5 so i'm sure the quality is high enough for this.
Your G5 has a maximum image size of 2592 x 1944 pixels. To print at 13x19", you'd need to crop to 2592 x 1773 pixels (to maintain the correct proportions of width to height for a 13x19" print).

This works out to 136 pixels per inch of detail being printed. As a general rule of thumb, you want to have 150 pixels per inch minimum for a print. When you get too much below this,you can start seeing the invidual pixels in the print and get jaggies, etc.

However, because many inkjets interpolate the image (adding pixels that were not captured by the sensor) you can get away with less than 150 (which is what you are doing printing a 5MP image at 13 x 19" size). But, you will see a noticeable increase in detail and quality when you go more than 150.

Now, in order to maintain the correct proportions of width to height for a 13x19" print size, you'd need to cut the photo into quarters. This means that each of the 4 sections would only be 1296 x 886 pixels (approximately 1.15 Megapixels each).

Personally, I would not try printingmuch over 5x7" with an image size like this -- much less 13x19".

Feel free to give it a try. Simply crop out a section from a 5MP Image about 1296 x 886 Pixels and print it at 13x19" size. Feel free to interpolate it first using something like Bicubic with Photoshop. Unless you have a subject type without much detail, and you are going to be viewing it from across the room, I don't think you'll like the results trying to print to 13x19" from a 1.25 Megapixel Image.
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Old Sep 2, 2004, 8:36 AM   #4
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thanks for your help,

would you reccomend splitting a picture and then printing each section in 5X7 or 8X10 size? I guess 13 by 19 is a little to big
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Old Sep 2, 2004, 11:27 AM   #5
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Tim:

Let me make sure I understand exactly what you're trying to do. Are you planning on framing each individual print separately for the effect you want, or are you going to try and piece them together in the same frame?

Also, where are they going to be hanging (viewing distance comes into play); and what types of photos are you going to be printing (portraits, landscapes with lots of foilage, etc.)?

In order to split a photo into four 8x10" sections, you would want to crop it to 2430 x 1944 first. Then, divide it into four images of 1215 x 972 each. This would give you the correct proportions for 8x10" prints.

When printed, this would give you approximately 121 Pixels Per Inch of Detail. You may find this to be acceptable (but I would recommend interpolating the image first).

You can easily test it by simply cropping out a 1215 x 972 pixel section from an image (of the same subject type you want to print this way), then printing it at 8x10" size to see what to expect.

This would be like printinga single 16x20" print from your camera.

For more detail, you could go to 5x7" prints. If you split a photo from your G5 into four 5x7" Sections, you'll need to crop it to 2592 x 1850 first. Then, divide it into four images of 1296 x 925 each. This will give you the correct proportions for 5x7" prints; and gives you approximately 185 Pixels Per Inch.

But, this wouldn't give you anything (going with four 5x7's), unless you're just going after the effect of splitting them into multiple frames(you'd end up with a smaller total image sizethan you'd have printing one image at 13x19").

You may also want to consider using a service to have them printed at a larger size (if you're not just going for the effect of multiple frames). Depending on the subject type, viewing distance, etc., you may be able to get away with prints as large as 20x30" (since you're not going to be viewing them from as close).

This only works out to around 86 Pixels per Inch of detail after the needed cropping to 2592 x 1728 Pixels for this Aspect Ratio (20 x 30"). So, you'd want to make sure the service used good interpolation algorithms to prevent pixelation (or you used good algorithms to interpolate the image before sending it to them). Some subject types interpolate better than others, and viewing distance will also play a big part as to whether or not you think the quality is acceptable.

You can also test this (which is what I'd strongly recommend you do). Simply crop out a section that's approximately 688 x 860 pixels (739,600 pixels total), then print it at 8x10" size on your printer. I'd carefully interpolate it first. If you use Bicubic, try increasing it in 10% steps until you get back up to at least 150PPI before saving it, or 1500 x 1200 Pixels (around1.8Megapixels). Make sure you use the same subject type you plan on printing at larger sizes (because subjects with a lot of detail don't enlarge as well).

Then, back away from the print to the same viewing distance you'll be using for the larger print.

If I were sending an image out to be printed, I'd check to see what the service requires. Some "rez up" the image for you, and are probably using more advanced interpolation algorithms than you would.But, others may want a minimum resolution before they'll print it at 20x30" size. So, you may need to interpolate more for some services. Worst case would be that they'd want 300 Pixels per inch for a 20x30" print, which works out to6000 x 9000 pixels (54 megapixels). But,most services will take it the way you give it to them (because their software interpolates when printing).
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Old Sep 7, 2004, 8:26 AM   #6
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thanks jim for your help, what I was mainly trying to do was split a picture up for a nice affect, as well as gaining a larger size. I see exactly what your saying with quality issues when doing this. Is it possible using the photo stitch feature on the camera to do this? When using this feature on the camera you are getting different sections of a photo. I dont know how I would compile these photos though so that when split up in different frames they would flow together. I doubt I can use that stitching program because all that does is make a panoramic out of it. LEt me know what you think, thanks so much you are very knowledgable.




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Old Sep 7, 2004, 11:16 AM   #7
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Tim:

The stitching programs are designed to create a Panaroma from multiple images; not separate one image into different sections.

Taking Panorams can allow you to create very large prints (each separate image used is still high resolution; so you can go very large this way). However, you'd need to take the photos like this to begin with (take a different photo of each section of the scene you want to stitch together later).

It would take a lot of practice (making sure you've got the lens focal length set to reduce distortion, overlapping each separate photo enough, making sure that exposure is locked between photos, etc.). I am not the person to ask about Panaromas, but some of the other forum members with experience in this area could probably help give you some tips.


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Old Sep 7, 2004, 11:47 AM   #8
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thanks jim, so basically if i'm going to split a picture into sections (enlarging each)then framing a good thing to split would be a panoramic because of the high resolution of each photo.

Thanks


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