David Elmore

I have loads of information about printing and mounting on REDIpix.com, so do I really have more to say?  In this blog I will post news of new products, improved designs, and tips for better photography and ways to use your prints. I will also tell you about promotions and ways to save money on high quality prints. Come back often to read stories about the development of our products.

Original photo after raw conversion

I process a large number of images submitted for printing and am saddened to see quality issues that could have been avoided with a simple change to a camera setting. Here I review the digital camera settings that are most important for obtaining great large prints.

Lower image shows effect from lower camera resolution

Resolution. Most new cameras now come with pixel resolution in the range 3-20 Megapixels, and you should always record all the pixels you have. A sharp photo taken with good lighting from cameras at even the low end of this range will look great on prints 16×20 or even larger. However, most computer monitor screens have only 0.5 to 2 Megapixels and photos on Facebook are typically under 0.5 Megapixels. So if you mainly use your photos for posting, slide shows, and small prints then you do not need all of the camera resolution, and you may be tempted to reduce the resolution in the camera to save space on your memory card and computer disk drive. The trouble is that you never know when you might get that great shot and want a large print for your wall, to give as a present, or to sell. Another benefit of full resolution images is that you can crop them later and still end up with a monitor-size image. In your camera settings menu the image size options should be easy to find. We strongly recommend that you always set this to the largest image size. It makes no sense to purchase a 10-megapixel camera and use only part of that capacity. The prices of high capacity memory cards and external disk drives have dropped considerably in the past few years so lack of storage space is no longer a good reason to lower your camera’s resolution and image quality.

Lower image was saved with lower jpeg quality

Image quality. To save storage space, your camera compresses the data from the image sensor into a jpeg file. This is a “lossy” compression which means that, while saving space, you are losing information resulting in an image with lower quality. You should always set the image quality setting to the highest possible value. At lower settings, “jpeg artifacts” will ruin large prints. These artifacts show up as extra dots or smudges near contrast edges such as in the sky where it meets the horizon and as cross-hatched lines in otherwise mostly smooth areas. We can minimize the damage by using filters in Photoshop, but image detail is lost and the resulting large print will look blurry. Although images at the highest quality setting are pretty good, to obtain the best quality and completely eliminate the compression, you should use raw files instead of jpeg.

Raw files. Most advanced cameras allow you to save the raw data from the image sensor. Although this isn’t for everyone, if you are looking for the best quality large prints you should definitely consider using raw files. This completely eliminates the jpeg compression issue and, in addition, raw files save more brightness information for each pixel, effectively increasing the range in brightness you can capture in one shot. Jpeg files store only 256 levels of brightness for each red, green, and blue channel for each pixel. Depending on your camera, this number is increased to over 16,000 levels for raw files. If your image does not need editing, 256 levels are enough because that is all printers use. However, if you want to for example increase the brightness of a shadow area so you can see some detail, you need this extra “bit depth” to avoid posterization (step changes where uniform gradients are expected). In this way, raw files add the equivalent of several stops of dynamic range to your camera. The down side of using raw files is possibly extra time between shots, extra storage space, and possibly extra steps in your workflow. If you use Lightroom your workflow will be unchanged, and if you use Photoshop you will first open your images with Adobe Camera Raw which is fast and easy to use. Be sure to retain your bit depth by using 16 bit images in Photoshop.

Noise results from setting the ISO too high

ISO. For digital cameras, ISO is the equivalent of film speed. When you have good lighting, you should set this to the lowest possible value (100 or lower). With higher values you will have increased noise which is similar to film grain. We can reduce noise in Photoshop, but, as with jpeg artifacts, you will lose image detail and the print will be more blurry looking. In low lighting, a higher ISO is needed to avoid blurry images from camera shake. If you set the ISO to automatic (the default or only setting for point and shoot cameras), then the camera will do a fairly good job of adjusting the ISO for the available lighting. With a manual camera and a poorly-lit still scene you can use a tripod and keep the ISO at a low value.

Upper image is overexposed (road is pure white) and lower image is underexposed (side of fence is pure black).

Exposure settings. With the latest digital cameras automatic exposure works remarkably well. The one problem we sometimes see is over-exposure where a white object, such as clothing, snow, or clouds, is clipped to pure white so that there is no detail or texture. This can also happen with only one color channel so that, for example, a red flower is pure red, again without any detail or texture. There are two ways you can look for and correct this problem in your camera. You can display the histogram before (on some cameras) or after taking the shot. If the graph is bunched up on the right and does not go to zero before the right end, then you have highlight clipping. With many cameras you can also set the display to blink black and white where there are clipped highlights. You might not mind clipping in a few small areas receiving specular reflections or overcast sky. The best exposure with digital cameras is the highest exposure possible without significant highlight clipping. With lower exposure you run the risk of clipping shadow areas and will have lower dynamic range. If you need to raise or lower the exposure after taking a test shot, most cameras have an exposure compensation setting. Use it to maximize exposure without clipping highlights if you want the best possible images for printing.

Color space. In an ideal world you would like your camera to be capable of capturing every possible color and your print to show all these colors. In the digital world, the image information is stored in a limited color space. The three main color spaces you should consider are sRGB, Adobe RGB, and ProPhoto RGB. If you use raw files, it does not matter what color space your camera is set to, but you still need to choose wisely when converting the raw files and setting your working space in your editing program.

The sRGB space is the smallest of the three which means that there are the most “out of gamut” colors that it cannot represent. Nevertheless, it is the default on most cameras and the only option on some cameras. Some printing labs accept only sRGB, and many portrait and wedding photographers find that it includes all the colors they require. If you do very little printing, then sRGB is a good choice since most slide show programs, browsers, and email programs do not have a color space setting and assume your image is in sRGB.

Adobe RGB is a wide-gamut color space and includes almost all of the colors available on today’s printers. We use this color space on most images and recommend that, for the best prints, you should set your camera to Adobe RGB if that option is available. The down side of this is that you should convert to sRGB before posting on the web or sending by email.

The largest of these three color spaces is ProPhoto RGB. It is so large that it includes colors you can’t see or print. The down side when using this largest color space is increased risk of posterization when using 8-bit images. Therefore we recommend using ProPhoto RGB only if 1) your images contain saturated colors that must be reproduced accurately in print, 2) you process raw files, and 3) you keep your images at 16 bits all the way from raw conversion until submitting to us for printing.

I am always looking for new and interesting media for our giclée printer. Last March I found out about a couple of different cloth media from LexJet. I tried them in our HP Z3100 printer and was really impressed with the Water Resistant Satin Cloth. It is a very thin but strong synthetic cloth made in China from Terylene. The weave is very tight and so the bright white ink receptive coating completely covers the weave and provides a completely smooth surface. It shows every detail like photo paper. The light areas of a print are somewhat transparent and so your print glows like a TV screen when you hold it up to a light or window. Even though it is so thin and flexible, the printer handled it well.

My first thought was to use it to sew some type of clothing from it. So we ran a piece through the wash. It came out very wrinkled and some of the ink and coating wore off of it. So that was not such a good idea, but the fact that most of the print was still there is indeed remarkable.

Gallery Wrap Elite on Satin cloth

Next I tried using it for one of our gallery wraps. Shown here is my first one (this is our grandson being friendly with one of our baby llamas). It worked perfectly the first time. The Glamour II coating sprayed on well as long as I didn’t apply too much in one coat. I could make it matte or gloss, although with the lighter coats compared to canvas I could not make it as glossy as I can with canvas.

The next thing I tried was making a banner. I made a loop in the top and bottom so I could slide in a dowel. Rather then sew the loop which would show stitching from the front, I used the same hot melt adhesive that I use for mounting on foam board. Although the satin cloth hangs nice and straight, this looked too much like a banner. So I took great interest when one of my customers, Terri Gold, brought to my attention a gallery presentation by Leslie Bartlett. He used a conduit made for hiding electrical cords on the wall. The white bars are called CordMate® made by Wiremold and is available in many homeowner stores. Leslie used the adhesive on the back to attach to the satin cloth and used two nails under the top side overhang to mount to the wall. The bottom is held by the weight of the bottom bar. We made several changes to the mounting and named it ArtRoll. Come back later for the rest of this story.