Lighting for Image Editing & Print Evaluation

[Kit-V]

[NOTE: I posted a question recently, but neglected to be more specific. For that I apologize. Subsequently, having deleted that post, I hope this one is clearer & elicits your responses. Thank you].

After moving into a new home recently, I am finally ready to take my first steps toward having some of my images printed. Toward that end, I opened an account at ProDPI. Using my calibrated NEC display, I softproofed my images using the proper ICC profile & sent them to ProDPI for a few test prints.

When the received the prints, I was quite pleased with the results except for an excessively warm color cast that was evident in all of the prints. Admittedly, one of the things I failed to consider was the ambient lighting used to edit my images & to review the prints. (My editing room has standard overhead tungsten lights). It seems to me that before I consider other factors that might have caused the warm color cast, I need to address the ambient lighting. Thus, I have a couple of basic questions:

1.  In order to achieve an accurate match between the display & the print, is it essential to edit my images & to eventually evaluate the prints under the same proper lighting conditions (e.g. 5000K lights)?

2.   Since (I am sure) this topic has been beat to death, could someone kindly point me toward a practical discussion on setting up a proper lighting environment for editing & print evaluation?

Thank you kindly for your help.

Kit

[Chris_Brown]

A specific viewing booth is best to evaluate your prints. The principle is that the light is of a specific color temperature and color rendering index (CRI). The color temperature is usually 5000˚K but some companies have introduced bulbs with a color temperature of 6500˚K (the higher the Kelvin temp, the bluer the white point).

Examples of desktop viewing booths:
GTI
Just-Normlicht

The CRI is also important. It indicates that the light sources transmit all color evenly across the visible spectrum. Where you can get into trouble is when your walls, ceilings and room lights affect your viewing booth/area. If possible, you want to negate any color influence on your viewing area by turning off room lights, or replacing the bulbs with daylight balanced bulbs, and painting walls near the viewing area a neutral gray.

To give you an idea of how it can be done, here's Jeff Schewe's work area:



It's impossible to know how "warm" your prints are without seeing them in hand. Did you output the files using an ICC profile that targets the ProDPI printer?

And, what kind of light are you using to evaluate the prints they sent you?

[HSakols]

I know two professional landscape photographers and neither one uses light box to view their prints.  They generally prepare their prints for the way they will be viewed which usually consists of spot lights that are way under 6500 K.  I don't understand the need for a lightbox?

[Chris_Brown]

I know two professional landscape photographers and neither one uses light box to view their prints.  They generally prepare their prints for the way they will be viewed which usually consists of spot lights that are way under 6500 K.  I don't understand the need for a lightbox?

They guys you know aren't wrong, they simply have their preferred workflow.

Most calibrated monitors are calibrated to a white point of D65 or D55 (for SWOP use, some use D50). When working on an image with this white point setting it's easy to evaluate print output using the same color temperature of light.

And most museum use very low wattage tungsten lights to avoid damaging any artwork with potential UV rays. I've seen a few galleries using D50 fluorescent bulbs with a UV inhibitor sleeve around the bulb, but that is still the exception.

The biggest problem with tungsten light is that it's very weak in the blue spectrum, and biases a prints color.

[Kit-V]

Chris,

Thank you for your input on light booths. This might certainly be a consideration in the future. However, for now I am considering using a desk top D50 lighting source for print viewing.  To answer your question... I used the ambient tungsten ceiling lighting in the room to view the prints. That is why I am considering a D50 light source as a preferable alternative. I would appreciate any thoughts you might have on this.

Also, is it essential to editing my images using the same D50 light source in an effort to achieve a more accurate print-to-screen match?

And, to answer your other question, I did use the ICC profile that targets the ProDPI printer.

Thank you. Kit

[Chris_Brown]

Kit,

Desktop lamps that provide accurate daylight balanced light can be found at:
Solux
GTI

Browse these sites for alternative solutions, too. Note that the Solux provides bulbs of different color temperatures for more closely matching the final viewing environment.

You mention your ceiling fixture. You can replace the bulbs with daylight balanced bulbs, but if the paint on your ceiling & walls is tinted, that will affect the color of light and its viewing characteristics. If you were to use a desktop lamp, I'd advise turning off other light sources to minimize color contamination of the viewing light.

The idea here is to get a viewing area/station that you can accurately view your output under. For some photographs you will print many copies until you're satisfied, and if the viewing conditions are causing you doubts then you'll begin to waste paper, ink & time.

Also, is it essential to editing my images using the same D50 light source in an effort to achieve a more accurate print-to-screen match?

That's the idea. When your monitor white point and your viewing station white point are the same, it is much easier to evaluate neutral tones for accuracy & neutrality. It also helps provide a relative comparison of saturated colors, deep tones and pastel tones.

However, many galleries use tungsten light at fairly low output levels. Many homes use CFL bulbs with non-neutral output. In a home, you'll also encounter, perhaps, artwork lit by tungsten but also by a window and table lamps using CFL bulbs. These viewing conditions have no standards, and it's understandable.

In the world of offset printing, D50 light with a CRI of 95+ is the standard (i.e., SWOP standard). I evaluate my proofs under D50 light at my studio. When those images get printed, the press operator evaluates the press sheets under D50/CRI95 lighting conditions and, in theory, what I looked at will match what the pressman looks at. But once the magazine/catalog/brochure gets to the end user, we have no idea how they'll be viewed. In a car? Airplane? At the beach? There's no way to control the end-user viewing conditions.

What can you do? Setup your monitor and a viewing station/area with white points that match as closely as you can, and as your budget allows. Get comfortable with the iterative cycle of adjusting/printing/evaluating your prints. Use the same type of lighting in your studio/showroom as you use to evaluate your work. When an image is purchased by someone who's going to hang it in their home, you & they need to understand that, due to the color of light falling on the print when hung in the customer's home, it may look different than when viewed in your studio or shop. At that point, you may want to make adjustments to the image file to correct the output for those viewing conditions, but that's up to you.

[Kit-V]

Thank you, Chris, for the thoughtful response. Truly appreciated.

Kit