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Old Nov 23, 2003, 6:00 PM   #1
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Default printing 5 megapixel pictures

I am a relative newcomer to the digital camera world and just purchased a canon G5.

I have been taking the images to various photo printing labs (wal mart, ritz camera, alphagraphics etc) and have been getting so-so results.

At alphagraphics I tried to print a black and white print of my daughter for an xmas card. I sent them a full resolution print (large images size, superfine resolution) it was a 2900X1800 pixel picture. Their image software converted this into a 39 by 28 inch image with a 72 dpi resolution. They claimed that if they reduced the size of this print, I would still have a 72 dpi print.

So I'm confused. I would assume you compress the pixels into a smaller space and get higher resolution (smaller pixels right?)

If they are right I can't for the life of me find anything on my camera to increase resolution.

Any suggestions? and Where have people had good luck printing pictures?

Thanks,

Brian Williams (Frustrated in Ohio)
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Old Nov 23, 2003, 6:49 PM   #2
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Hi Brian,

I may not be much of a help as I still am learning myself. Pixels & resolutions are still something that I need to learn.

I do mine by site and can't quite explain but I get good pictures.

I use an editing program, Jasc Paint Shop Pro 7. In the begining, after editing Tiff photos, then saving photos (to JPEG) and unhappy with the results...I discovered that the programs compression was set to a default setting. I then went in and set it to the best setting.
With this, I was getting good pictures.

If I wanted to send these photos via email, I would have to resize...always saving under a new file name.
As a rule, I keep all original Tiff photos, uncompressed JPEGS and modified JPEGS (the latter being so I can send these via email).

I have had a few photos of mine printed online, both at Ofoto and Snapfish. Ofoto being my favorite of the 2.
When subscribing, you will receive free/discounted photos.
If I remember correctly, Ofoto (after uploading your photo to their site) will tell you what sizes your photos could be printed.
If it is a good resolution, you should be able to get a large print, if you so choose.
By the way, both places only accept JPEGS.

Just for fun, why don't you try uploading to Ofoto and see what recommendations you get for print sizes.

Surely someone more technical can better answer you and hopefully they will

Good luck!
~Kate
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Old Nov 23, 2003, 7:00 PM   #3
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You don't need to worry about resolution at all. Your camera is giving you 5,220,000 pixels to work with and that is independet of resolution. Resolution in dots per inch (dpi) is meaningless actually. Just send the image to the photo lab and tell them the size. They will take care of the rest. If you are not getting good results from them then try a different lab.

The dpi is not at all useless, it just tells how big the printed image would be at a given dpi value.
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Old Nov 23, 2003, 7:05 PM   #4
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By the way, if you edit a picture, it is always better to edit the Tiff photo and THEN save to JPEG.

When you zoom in while using Canon zoom browser, a very good picture will show little pixelation.

I just went in and checked some of my photos that I had printed online and with your image size...you should have gotten good photos.
I'd definately try the online processors.
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Old Nov 23, 2003, 9:12 PM   #5
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Luis is right. Pixles and dpi can be confusing. Just remember what dpi is. Dots per inch. The same size digital image, will have different dpi when it is printed, depending on the size of the print. A 4x6 will have a higher dpi than a 8x10.

The confusing part is this "72 dpi" we all hear about. That is the resolution of your VIDEO MONITOR ONLY! Your monitor can only display 72 dots in one inch. If you are viewing an image with more pixles than your monitor, your computer will throw away the extra pixles. This is why a good print will be much sharper than when it was viewed on your monitor.

I think the guy you talked to at the photo lab does not know what he is talking about.

Hope this helped!
Darrell
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Old Nov 23, 2003, 9:50 PM   #6
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Quote:
If you are viewing an image with more pixles than your monitor, your computer will throw away the extra pixles. This is why a good print will be much sharper than when it was viewed on your monitor.
That's good to know! I hadn't thought of that. No wonder when my photo's came back, they looked crisper on paper than the monitor. lol :lol:

Brian, I just thought to let you also know, since it just came to mind, Yahoo does have a forum dedicated to the Canon G series cameras at: http://groups.yahoo.com/group/canon-g-plus/

It has been some time since I've been there but last I was there, I found the group to be very helpful. One individual stands out: onehotrx7
I dropped by there before coming here to see if he is still there. He is.

Not only are they helpful but the posters are (of course) familiar with your camera. Quite a few are great photographers, with a few pros lurking there.
You may find inspiration, also, when viewing some of their photos.
Nice to see what the camera & the person behind it is capable of doing.

Some posters from that forum subscribe to this site also:
http://www2.photosig.com/go/photos/b...ories?typeId=6

Here you can find pictures taken from each camera make & model.
Some might be listed under Canon G5 or Canon Powershot G5 etc.
I will warn you, however, that some people's idea of "Art" differs from the next person. There are some pretty risque pictures there so, if you mind-forgoe the site.
Most pictures are not but some are. Just thought to mention.

The Yahoo Canon site, I probably should get active in that club again. I have much to learn, yet.

Anyway, once again~good luck.

~Kate
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Old Nov 26, 2003, 8:33 AM   #7
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DPI matters when you print, and one way to ensure this is to, in Photoshop, swap DPI from 72 up to 250 or even higher.
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Old Nov 26, 2003, 8:57 AM   #8
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Red Viper: I think you are confused. Increasing the DPI in Photoshop does nothing to improve the PRINT quality. It is no different than a digital zoom...

Darrell
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Old Nov 26, 2003, 9:41 AM   #9
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Just remember that the shop photo printer probably does no more than 300dpi. That's as much as the eye needs and what many happy snappy film people are now getting off the same printers.

So a 6X4 print uncropped from your 5Mpix camera will be down sampled to about 2Mpix ((6x300)*(4x300)) - did you really need that 5Mpix camera? Yes, but only if you are cropping an image or making a larger print. VOX
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Old Nov 26, 2003, 11:03 AM   #10
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Quote:
Originally Posted by Red Viper
DPI matters when you print, and one way to ensure this is to, in Photoshop, swap DPI from 72 up to 250 or even higher.
This is a common misconception. The cameras don't take photos at 72dpi by default -- that's just how your software is displaying them (it's the common size used by older monitors, so it's become somewhat of a display standard for image editing software).

For example: A typical photo will be taken at around 2560 x 1920 pixels with most 5MP models.

So, if you are displaying it in software, at 72dpi, you get a very large image size on screen (2560/72ppi = 35.555 inches, 1920/72 ppi = 26.666 inches). So, on an older model monitor (as the 72dpi display standard was based on), a 2560x1920 pixel image would appear to be around 36 x 26 inches large (with monitor size variation entering the equation, too).

But, when you send this same image to a printer, the pixels per inch sent, depend on the print size.

For example: if you wanted the "perfect" 300dpi print , your 2560 x 1920 image would translate to an 8.53" x 6.4" print (2560 pixels/300 = 8.53, 1920 pixels/300 = 6.4).

However, most users won't see any difference between 200dpi and 300dpi (unless you look at the photo under magnification).

The printer driver should use all of the resolution (as long as you don't have any resize/resample boxes checked).

Actually, what it's really doing, is taking the image you send it, then converting it again, into the actual DPI printed by the printer model. It knows nothing about what your software is displaying it at -- only the actual resolution of the image in pixels (around 2560 x 1920, in the case of many 5MP models).

If you are using a 3rd party printing service, ask them how many Pixels Per Inch (minimum) is needed for the desired print sizes (most don't even care -- but for very large print sizes, this can be a problem).

As far as print sizes, many will argue that 150 pixels per inch is plenty of resolution, with anything more a waste, since the human eye won't be able to tell the difference at normal viewing distances.

Others will argue that 200, or even 300 pixels per inch is necessary for the best quality. Again, I've found 200PPI to be plenty.

Here's a chart that may help. You'll probably find that the "good" column is all you need (unless you're going to examine the print under magnification).

http://www.cordcamera.com/products/d...ct_ratios.html

IMO, anything above about 180PPI is fine for prints up to 8x10", and even less is can be used for larger prints (because you'll be viewing them from further away). The printer used can make a difference, too -- as many ink jet printers "optimize" the input they receive for photos. Dye Sub printers may require more pixels (300 ppi is best for some dye sub printers).

Here's another chart that takes popular digital camera image sizes, and shows how many pixels per inch you'll be sending to the printer driver for popular print sizes:

http://home.earthlink.net/~terryleed...tables.htm#ppi
Also, you can interpolate an image using software (you shouldn't need to, unless you are printing VERY LARGE prints). This does not increase the detail captured originally, but it does add pixels (based on the value of adjacent pixels). This lets you print larger images without pixelaton.

A good free package is irfanview. It has a very sophisticated Lanczos Filter based interpolation algorithm (you'll find this option under the resize/resample menu option). You can download the software (free) from this link:

http://www.irfanview.com

Also, you may want to be aware that standard print sizes can result in cropping of your digital image. Refer to this chart, to determine the percentage of your image that will be used, at popular digital camera sizes, for standard prints:

http://home.earthlink.net/~terryleed....htm#frameutil

Some printing services (like Photoaccess.com) offer "digital size" prints (no cropping of your photos). Others don't. So, you may want to crop your photos for standard 4x6" prints. But, don't mess around with DPI count (or check any resize/resample option boxes). More resolution than needed is fine to send to a printer.

Now, there is a flag for dpi in the image header, but Changing it is only changing a byte in the image header and doesn't really change the image at all. But, I'd advise to never try and change this setting with Image Editing Software, as some software may try to resize an image based on this flag. Printing software ignores it.
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