Imaging for Output Part 1

When creating an image for output, one must remember the old adage, “Garbage in… Garbage out”.  If your digital file is not the best it can be then the resulting print will not be very good either.  The larger the output the better the image must be.  Many file defects can not be detected in a 4×6 inch print, but would be glaringly obvious in a 12×16 inch or larger print.   If you are reading this article, one must assume your goal is a larger and better image.  In many respects the quality of your digital file is the the most important factor in output.

The first step is to become familiar with your camera or digital capture device. Take the time to read and understand your camera’s owner’s manual.  Be sure your settings are set on the largest image your camera can capture.  It does not make sense to pay for megapixels and set your image size to small.  Memory space is no longer expensive so should not be an issue. The larger the file the larger the output. If your camera has the capability to shoot in Camera Raw, it is wise to use it. If you are used to shooting in jpg and just started using camera raw, you may find your images seem flat, not as vibrant. That is because the camera applies adjustments to the jpg image.  In camera raw, you must apply the adjustments. Some other advantages of using Raw are an uncompressed file, more digital information, more ability to edit and adjust the final image, and usually a larger image.

It will require some digital editing, but if your objective is to create the best possible printed image, then it behoves you to learn to edit your work.   There are many factors that affect the quality of your photo. If you find you are unable to hold the camera steady – use a tripod or a monopod. If you are seeing a great deal of digital noise (graininess), lower your ISO or use a flash.  Although there are software fixes for issues like digital noise, it is best to have a great shot to start rather than try to fix a bad shot.

DSLR cameras usually have a menu option for setting color space.  The default is usually sRGB. The sRGB color space is the color space of choice if you only intend to post your images to the web. It is the space most computers and other devices use.  However, sRGB is a limited color space, compressing colors and limiting color gamut.  The most widely used color space for output is usually Adobe RGB.  It has a wider gamut (more colors) and is compatible with most digital printing systems. If you set your camera to shoot in the Adobe RGB color space, you will want to use that color space in your  digital editing software as well. It is not advisable to go from one color space to the other  for output. By shooting in sRGB then converting to Adobe RGB in your editing software, you might find a drastic difference in color appearance. If you are using Photoshop for your editing software, you can designate your color workspace.  Go to Edit> Color settings and select Adobe RGB for your working space.  Under Color Management Policies it is a good idea to choose to “Preserve Embedded Profiles”  and to have Photoshop ask if there are profile mismatches. I do not change the color space if there is a mismatch for the color space as it changes the colors. If your camera does not have a setting for color space, it is best to assume you are shooting in sRGB.

Image resolution is another concern when thinking about image output. Resolution can be very confusing as it refers to several very different things. There is first the image resolution – how many pixels per inch in your digital file.  There is screen resolution, the pixels per inch on your computer screen, and finally there  is print resolution- how many points per inch of ink the printer puts onto the printed media.  All of these measures of resolution are different but are often confused. For this part of the discussion we are mostly concerned with image resolution.  The image resolution is directly correlated to your image size.daliah100

I often hear and see the concept that to be printed an image must be 300 ppi (pixels per inch).  If one is planning on outputting to a published source – newspaper, magazine, etc., that is correct.  The publishing industry maintains a standard of 300 ppi and if an image is sent in another resolution it will become a different size when placed into the publisher’s document.  For consistency and  convenience published material should be submitted at 300 ppi.   Often images published in newspapers and magazines are small.  Meeting this size requirement is not difficult.

image size box

The 300 ppi publishing rule does not have to correlate to image printing, however.  If the image is good, it can be printed with its native resolution to whatever size it continues to look good. I have read numerous articles about what resolution the image file must be in order to have a great print. Despite what many “experts” say, in my 10 years as a commercial digital printer  I have printed images at 72 pixels per inch resolution that look as sharp or sharper than images printed at 300 ppi.

The major factor here is “native resolution” – The actual pixel size that your camera captures.  When you import or download your image from your camera to your software it is the pixel dimensions set by the image sensor of your camera that dictates the resolution size, and not the other way around. That is the resolution does not (within parameters) dictate print size but the print size dictates the resolution.  Consider the first image size box. The native resolution of this image is 5616 pixels x 3744 pixels.  By resizing the document size resolution I can change the image size output. If I wanted to print this image at 8×12, it would increase the document size resolution to 468 ppi but not alter resizethe native resolution of 5616 pixels x 3744 pixels. If my original image is sharp at 100% view in Photoshop, it will print sharp at 12×8 or 23.4×15.6 or even 78 x 52 at 72 ppi.  (One thing  to note is that at the smaller sizes the printer device will eliminate pixels but it done by algorithms and is invisible  to the user). The images of the daliah above would print fine at 72ppi  with the native resolution, but as you can see would print badly at 72ppi when up-resed.

If you decide to up-res an image (add pixels) then you are changing the native resolution and your image will begin to degrade to the point where it is often destroyed or at the very least quality compromised.maxsize box

Fine Art Photography: Imaging for output, Three Part Discussion

iris-as-printed

The end result of photography is not as it used to be. In the days of film photography the only way the photographer could view the image was as an actual printed photograph or sit in a darkened room and

original on screen irisview a slide show. If the processed photo was excellent the photographer might consider an enlargement for display. Unless the photographer had access to a dark room the film and print were created by “photo labs”. The photographer usually did not have much input into how the image was processed and developed. The only way others could view or enjoy the work of the photographer was to actually be there and view the physical print or the slide show. Occasionally, professional photographers were published in magazines and were able to share their work with a larger audience. Most photos, however, were developed, printed to a small format and then stuck in a drawer and forgotten.

Digital imaging and the internet have changed everything. Photographers can now share their work with the entire world. Through social media sites like Flickr, Smugmug, Facebook or email photographers can display their work and get feedback. With tools like Photoshop, Lightroom or Picasa the photographic artist can enhance, create and process his work in the “digital darkroom”. With the cost of film development eliminated, an artist can be as prolific as she wants to be. One need never create an actual print to consider oneself a digital photographic artist. As one develops as a photographic artist in this digital age, the mastery of imaging software is the first step in becoming a fine art photographer.

 There comes a time, however, when the photographer wants to have an actual print. Whether it is to enter competitions and art shows or to hang on the wall, the printing of one’s digital work is a logical next step. Often there is a surprise and disappointment when the resulting print does not come close to matching the image on the computer screen. The photographer then realizes that there is another element to learn in this process. There are many factors that effect digital imaging output. From defining and working in a color space to specifying profiles for the print media, the variables in printing can be daunting and mysterious.

In this three part discussion, we will start with image capture, processing and color space. Part two will discuss media profiles, screen calibration and print drivers and software, part three will cover the printing process, printers and media.

Color Mode: RGB vs CMYK

As a giclée printer, I often see confusion about color mode.   For this discussion I will focus on RGB and CMYK, although there are other color modes with different functions and uses.

RGB (red, green and blue) refers to the additive or “light” color process.  When these three colors of light are combined; white light results. The absence of these colors of light appears as black. This is the idea behind display devices, like your TV or Computer Monitor.

CMYK (cyan, magenta, and yellow) are subtractive colors. These colors reflect light back. Theoretically when combined the three colors should produce black. Because the resulting color is not a “pure” black, printers add black (K) to the combination resulting in CMYK.

RGB refers to light (additive) while CMYK refers to pigment, inks or paint (subtractive). Because all printers, be it inkjet, laser, or offset use the subtractive process to produce color it seems reasonable that when creating files for printing one would work in the CMYK mode. This is true for traditional color printing often called offset or 4-color process. The technology behind this printing process is to create 4 separate printing plates. Each plate was originally created by photographing the image to be printed four times using a filter for each color.  The resulting separations representing red, green and blue were then reversed to create the negatives for its color opposite.  For example red is opposite cyan on the color wheel, because cyan is the result of mixing blue and green light and the absence of red light.

Although the inkjet printers and devices that are used today by many professional printers use pigmented inks that are CMYK or variations of CMYK, the file mode format should be RGB.  This is because the files are converted by the print driver or RIP (raster image processor, fancy name for print drivers), into CMYK.  If the files are not in the RGB mode, this process still happens but sometimes with unwanted results because CMYK has a smaller color gamut.

So should you produce files in RGB mode or CMYK mode? The answer is it depends. If your files will be sent to a printer who uses an offset or 4-color process press then you should convert your files to CMYK.  If your printer uses a digital process and prints on an inkjet printer, you should keep your files in RGB mode. If you are unsure what process your printer uses, ask.  If you want the best possible color for your image, be aware of how it will be produced.