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Dash of Inspiration – Artifacts … the Facts

March 19, 2012

A Dash of Inspiration, A Cup of Creativity by Doreen

Artifacts … The Facts

This has been an interesting topic of discussion, so I thought it might be fun to further investigate the Definition of Artifacts and how it relates to those of us creating high-quality imagery.  So let’s start with the definition of Artifact in the context we are referring to:

Here are two definitions of Artifact appropriate for digital mediums since artifacts are usually the result of something we choose to incorporate into our creation; either during camera setup for a photograph or during digital scanning or processing.

The Science Dictionary Definition:

An artificial product or effect observed in a natural system, especially one introduced by the technology used in scientific investigation or by experimental error.

Computer Desktop Encyclopedia:

A distortion in an image or sound caused by a limitation or malfunction in the hardware or software.  Artifacts may or may not be easily detectable. Under intense inspection, one might find artifacts all the time, but a few pixels out of balance or a few milliseconds of abnormal sound often go undetected.

Part of the reason we are seeing more and more ‘artifacts’ in imagery these days is that digital cameras often shoot in JPEG format which is a compressed file format.  From the the moment of capture, compression of data begins and every time that file is saved in a JPEG format it compresses more and more data, and every time that JPEG is opened, it has to try and recreate missing data which is where the artifacts come from – pieces of data CREATED TO REPLACE MISSING IMAGE DATA – ouch!

Courtesy of Harvard.edu

Today most DSLRs are offering a RAW File Format to shoot in, as do all Pro-Level Cameras.  This is definitely the way to go if your camera offers it. Though I won’t get into all the reasons why, let’s say reducing the artifacts from compression loss by not shooting in a compressed format is one very good reason.

Okay now, let’s look at many of reasons that artifacts end up in our imagery so we can better recognize it in our own images and work to avoid it:

  1. In JPEG captured/saved images there are several types of artifacts which can haunt your image:
  2. Posterizing in areas which should be smooth gradients
  3. Staircase noise (jagged) around edges with curves
  4. Buzzing or what some call “mosquito noise” around edges
  5. Blockiness/busy areas sometimes called quilting or checkerboard effect
  6. A blurring or smudged appearance and/or light halos around dark areas of an image
  7.  Color distortion, known as color noise or in a gray-scale image it can appear grainy or patchy

Courtesy of the Yale Library

It’s important to keep in mind that these types of artifacts can appear in ANY DIGITAL ART form, regardless of whether it began as a photograph or not.  If you save your work in JPEG format as you work on it, you are doing irreversible damage to the data.  When artifacts appear in other image formats (other than JPEG) it usually is because they have been converted from a JPEG somewhere in the history of the image file.

In photography under certain conditions, the image captured by your DSLR can have too much information, creating color noise and digital artifacts in the photo; particularly when you’re shooting at low-light levels (under-exposure) and/or shooting with an ISO higher than 100.  Color noise artifacts can also be a found in images captured by low-end/low-resolution digital cameras.

Courtesy of Darren Rowse

Generation Loss refers to the loss of quality between subsequent copies of data such as; saving a compressed digital file over and over again. Anything that when copying (like making a copy of a copy on a copy machine) results in a further reduction in quality which is considered a form of generation loss.  Here is another example:  For those of us who have shot photographs on film, that negative becomes the First Generation. We then make a print, that is the 2nd Generation.  Now if you scan that print in order to get a digital file, that is Third Generation. The greeting card or print from that digital file is the FOURTH Generation. You will see a significant loss in quality from the 1st generation to the digital version.
In digital cameras, artifacts may be produced when performing digital zoom. When analog material is converted to digital, tiny discrepancies (quantization errors) may result (see below for links to learn more about digital vs optical zoom).

Courtesy of Mobil Phone Reviews

 Scanned images – whether scanning a negative, photograph or artwork into digital file format, they all can have noise caused by the scanning sensor.  Scanners are difficult tools to use to truly create a hi-resolution, artifact free, color-balanced file worthy of using on your Print-on-Demand sites.  You really need to use a good quality photo-scanner, so you can make use of the extensive software they come with which allow you to correct color noise in specific channels while preserving the edge and image details for a fine-tuned noise reduction scan.

You can and should learn to recognize these effects in your own images, plus you will know how they got there and how to avoid them in the future.  Though there are many ways to reduce artifacts in images out there, there is really no way to remove them entirely and in most cases this means that the image quality is just not good enough to be considered something you would print and sell.  So I have not offered any links to ways for artifact removal.  Instead I’ve offered some links to avoid them by making better choices.

How to Choose the Right ISO for your Digital Photography by Darren Rowse

Understanding JPEG Formats from the Yale Tutorial Library

How CNET Central Tests Digital Cameras

Learn About Orb Artifacts Caused by Light Sources

Optical vs. Digital Zoom by Photoxels

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8 Comments leave one →
  1. March 19, 2012 10:55 am

    Doreen, very interesting post. I must admit that until now I wondered what folks were talking about when they used the term Artifacts.Thank you.

  2. Janet Lee Designs permalink
    March 19, 2012 5:48 pm

    Wonderful information Doreen, thank you for sharing!
    Janet Lee

  3. Donna Lorello/Sunshine's Creative Endeavors permalink
    March 20, 2012 12:00 am

    great article as usual. I do shoot in RAW but have a question – when creating the digital cards for GCU, what is the best format to work in if JPG or PNG is what we upload in?

    • March 20, 2012 1:30 am

      Hi Donna – here is the best practice:

      Save your RAW file as a Photoshop native format or a TIFF and do all your creation using layers in one of those file types, always leaving the important layers un-merged so you can easily modify them if needed or add them to a future design.

      When the card is ready for GCU, then save a copy that is merged (flattened) in a new name.

      Though GCU accepts JPG or PNG, I only use the PNG format when I have a transparent background. All other times I use a highest possible resolution JPG and since it’s never been modified, it has no artifacts when saved at maximum quality.

      Did that answer your question?

      • Donna Lorello/Sunshine's Creative Endeavors permalink
        March 20, 2012 8:33 pm

        yes, it does. THANK YOU 🙂

  4. March 20, 2012 5:43 pm

    Hi there Doreen,

    I don’t always comment, but I do keep a separate file for all of these helpful and interesting posts filled with tips and inspiration so I can come back to them as I am able to absorb more and more.

    You are always so helpful in the Forum too, you had caught my attention about the loss of quality of a photo once a jpeg gets saved and re-saved, I had definitely fallen prey to that one earlier on, now I also know its proper term, Generation Loss.

    Who knew what jpeg stood for? Not I . . . (Joint Photographic Experts Group).

    Many thanks for the time you take to share your talents, experience and expertise Doreen!

    Springtime sunshine to you from Toronto,
    With warm regards,
    Sri

    • March 20, 2012 6:04 pm

      Thank you Sri for stopping by and I’m always glad when I can pass along bits that will help others to avoid the mistakes I made early in my journey 🙂

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