Saturday, July 21, 2007

Resolution

This post is a little sidetrack. There have been some questions on the QuiltArt list about the possibility of people "stealing" images from web sites and blogs and using them for nefarious and commercial purposes. One person pointed out that such low resolution images are not very useful for commercial purposes, so they were not worried. Another chimed in that it is quite easy to increase the resolution with "a good graphics program," therefore making such theft quite possible.

I was taught that while it is possible to increase the resolution of an image in Photoshop, it accomplishes little in terms of producing a usable high resolution image, because the program only guesses at what the missing detail would be. I was so indoctrinated in this belief that I have stood by it staunchly. I also hear that increasing the resolution in increments produces better results than simply increasing it in one step. I decided to do a little experiment and share it here.

Figure 1. This is the image I started with, scanned, full size at 72 ppi.







Figure 2. This is the same image reduced to 30 ppi. Really terrible isn't it? You can see the individual pixels at this resolution.
Figure 3. This is the 30 ppi image, increased back to 72 ppi in one step. It smoothes out the pixelation through the process of interpolation, but much of the detail has been lost—for example none of the stitching which you could see in the original has been restored and it's all pretty fuzzy.


Figure 4. This is the 30 ppi image restored to 72 ppi in 4 steps, about 10 ppi per step. I can't really see any difference between this one and the last.

So my conclusion is that what I was taught stands. I don't think increasing resolution by any method (at least in Photoshop) produces a high quality image. And I continue to be unconcerned about the possibility that someone will steal my quilts to print posters and coffee mugs.

10 comments:

  1. Granted,I am using my wee laptop, but I do not see that much difference in the photos. The only difference is when I click on the second one, it comes up as a smaller image. I will look again, tomorrow, on my flat screen monitor.

    I have increased the size of images a few pixels at a time and find that is is less than perfect, but will work in a pinch when you can't reshoot something. I had this problem when I was putting images on my web site.

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  2. Hmmm. Interesting. I do have a very good monitor, but I just took a look on Ray's laptop and could see significant differences between the first three images. The fourth looks the same as the third.

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  3. kristin L12:40 AM

    I'm no computer geek, so I don't know all the ways one can protect one's images, but something I use on my blog is "Hotlink Protection." It doesn't keep anyone from right clicking and copying an image, but it does prevent them from copying the link location and using MY bandwidth when displaying my image on THEIR site. I also add a watermark to my images. Sure, I keep it to the edge where it's not so distracting and someone could crop it out, butI hope that it's a small reminder to would-be theives that the image is mine. My understanding is that most people that steal on the web are doing so because they don't know any better. Those who are serious theives are probably going to figure out a way to hack through any protection we throw up at them and there's nothing we can do but keep our fingers crossed that our lil ol' art blogs are of no consequence to someone looking to make a big profit off lots of views and ads.

    BTW, thanks Terry for teh demonstration. I was tought the same thing about resolution and agree with your findings.

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  4. I guess if someone is determined to steal, they will find a way. The most I do is print and date my images should I ever have to prove I own it in court.

    As to hotlinking, I have had several MySpace people use my images as background. If they don't stop after one request I replace the image with something really nasty. Works well.

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  5. Fascinating topic, I have been wondering about the wisdom of having a whole body of work 'out there' unprotected! And I have never heard of hotlinking. How do you identify if someone is doing it to one of your images? Thanks for sparking this interesting discussion, Terry!
    And BTW I love the old building in your previous post!

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  6. What size do you reduce your pictures to before posting them? Is there a set standard? I'm new at blogging.

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  7. OK! I am down in the basement on my large screen and I can definitely see the difference. You know that my IBook is the teeny weeny one. I can definitely see the differences. But, in a pinch, if you can't reshoot something, it can be the solution.

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  8. For Exuberant Color - I size most of my photos for the blog at 400 pixels wide (by whatever height they turn out to be)and 72 ppi. That seems about optimum, according to my experimentation. If photos are wider than 400 on some browsers they either knock the sidebar to the bottom, or they plunge themselves to the bottom of the sidebar.

    For Gerrie - I agree that upsizing an image by a small amount is sometimes better than nothing, especially for posting on the web. What I was really addressing is the idea that one could take a small 72 ppi image from a blog or web site and increase the resolution enough to make it usable for commercial printing at 300 ppi and probably at a larger size as well to reproduce as posters, etc.

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  9. I'm just thinking that I would be so flattered if someone wanted to use one of my images! :-)

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  10. Jane Ann8:29 AM

    Yeah, like Deb I don't think I need to worry about being pirated. But this is an interesting topic. I too am wondering how you know who is using your images??

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