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Computer Related Articles

Calibration of your Printing process

Ever wonder why your prints don’t always look like what is on your display?  Why do we need to calibrate our equipment to get the color renditions we want?  Let's take a look at the whys and the hows of getting better color prints at home on your existing equipment.

To Start with, the processes used by the various pieces of equipment in personal computers differ in the way they handle color reproduction. We'll focus on monitors and printers.  This doesn’t even consider scanners.  Monitors use an additive RGB (Red-Green-Blue) process to reproduce color.  Red, green and blue when added together will produce black.  The printing process on the other hand uses the subtractive CMYK (Cyan, Magenta, Yellow and Key (Black)) process.  Don’t worry about the additive and subtractive terms; they refer to how light waves interact with your visual system. 

To get your color printing to match what is on the screen, you need to calibrate both your monitor and your printer.  There are a myriad of ways to do both but the real key is to calibrate your monitor before your printer.  You can calibrate your monitor visually or mechanically, depending on how critical you are with the color prints you’re making.  I found a few websites that have links to some really valuable tools for visual calibration.  If these work for you, great, if not you will need to invest in some of the hardware/software products available for monitor calibration.  I suggest you do a web search for calibration tools. You can start with the tools embedded in your computer's operating system (e.g. Windows 10). If that doesn't meet your needs, there are many tools available that can be purchased on line.

Color Management

Digital photography has added a lot of new “buzz words” to our vocabulary. One of the most misused or perhaps least understood is “color management”. Discussions of color management lead to more terms like color space, rendering, sRGB, and so forth. We figured a brief foray into the realities of digital color is warranted, so we can utilize the new tools we have.

What does color management mean?

Essentially it’s the catch-all term that describes the process of making sure the colors of your subject are displayed the way you want them on the medium of your choosing, and that you can achieve that result consistently! First let’s define a few terms:

Workflow is the process or steps used to go from a captured digital image on a media card to a completed image ready for use or for storage

Color space is the portion of the color spectrum that is available to the output device (monitor, printer, etc.) for display of the image. In other words, how many colors can you hope to reproduce.

Rendering is the software process of converting a RAW image into a usable file in a specific color space. This word comes from rendition. Another techie convolution of the language.

This month we’ll concentrate on color space. The first step in color management is determining the color space in which you want to work. Remember that RAW files are “rendered” to the color space by the camera’s internal software or the post processing software in your computer. If you shoot only RAW, the rendering must be done in the post processing on your computer. If you can select multiple output files such a RAW plus jpeg, you can specify the color space for the jpeg files.

You should select your color space based on the planned use of the image. Most digital cameras will allow you to select Adobe RGB or sRGB. Adobe RGB has a slightly larger gamut of colors and is less saturated than sRGB. Adobe is more closely correlated with ink jet printers. If you are more interested in viewing your images on a monitor or projecting them with an LCD projector, the slightly smaller color gamut and more saturated sRGB color space is better. Post processing programs also allow CMYK color space which is more suited to publication formats. It’s possible to create different files from the same RAW image in various color spaces using the computer’s RAW conversion program (Photoshop™ as an example). Next month we will continue the work flow and color management discussion. We’ll look into calibration of monitors and printers.

Data Management

Data management is the industry buzz word for how you handle the images you have in digital format. Data management starts with selection of memory card size and goes all the way through the file structure and the back up process you develop. These decisions are really driven by the type of shooting you do. Consider the following notes and decide what fits your needs.

1) Select a memory card size that meets your needs. I personally feel that either 32 or 64 GB is a good size. These hold up to several hundred images in RAW format. Anything bigger could mean that your entire two week trip is on one card and could be lost or damaged. Anything smaller means you have a lot of cards that may get lost. If you shoot a lot of video, larger cards (128 or 256 GB) are warranted.

2) If you’re on a long trip using more that one or two cards, once you fill a card you have the choice of transferring it to a laptop or other portable device OR carrying enough memory cards so you can bring home your images on the cards. These cards are very rugged and immune to things like airport x-ray machines. Prices are dropping so this is much more of a realistic approach than it was just 2 years ago. As with any decision the “pros” have a variety of opinions. Some just use the cards; others make two or three copies on hard drives. My preference is to download images from memory cards once a day on to my laptop, make a second copy to a portable hard drive, and keep the images on the memory card. That way I have three copies. I don't reformat the memory card until I get home and download the images on to my home system and do my back up process.

3) Once you do get home, you really do need to consider your storage plan. A key decision is back up. Backing up data can be summarized in two words “DO IT”. Computer hard drives are electro-mechanical devices that will fail – some day. Now the question is what is the right way to back up data?

4) A starting point is to do a quick edit of your images. Then with your RAW images edited to remove the true discards, store them in a file on your hard drive in the most compact manner you can. Make at least two copies on hard drives. Additionally, an additional copy on a write once archival (not re-writable) DVD is another idea. Blank DVDs are cheap and provide good insurance. Keep the two in separate places if the images are really special. Then you can rearrange your files on the hard drive. This is where a good batch processing program (like Lightroom™) can be helpful. You can annotate each image with the DVD identifier in one step.

5) Now once you have started to do your image processing with Photoshop, you can also make copies on other DVD’s of the resultant jpeg or psd files. That’s up to you, but you’ll have your original RAW images on a fairly archival media. Do remember however that DVD’s are not permanent like old Kodachrome™ slides. They tend to deteriorate so it’s a good idea to rewrite new ones every few years.

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