Process Troubleshooting, Identifying the Problem

Effects of Viewing Conditions

Under certain types of illumination, the hue of prints on EKTAMAX RA Paper can appear warm. A silver-based black-and-white image reflects all frequencies of light equally, so a slight deficiency in one color of the viewing light will not have an adverse effect. A chromogenic image—e.g., an image on EKTAMAX RA Paper—is formed by dyes that have specific color absorption and reflection characteristics. Dyes do not reflect all frequencies of light equally. Instead, they reflect only specific wavelengths of red, green, and blue light. If a light source is slightly deficient in green light, a chromogenic print may look very pink (magenta) depending on the dye and the green-region deficiency of the light source.

To evaluate and display prints, use light sources such as tungsten and tungsten halogen/quartz halogen. These light sources provide a continuous frequency distribution of energy in the visible spectrum, and the image will appear neutral. Non-continuous light sources, such as mercury vapor and some fluorescent tubes, can give the image a slightly pink appearance.

A good average viewing condition is a light source with a color temperature of 5000 ± 1000 K, a Color Rendering Index (CRI) of 85 to 100, and an illuminance of at least

50footcandles (538 lux). Fluorescent lamps such as the cool white deluxe lamp (made by several manufacturers) meet these conditions. You can also use warmer lamps, such as the Phillips 5000 K Ultralume, or a mixture of incandescent and fluorescent lamps. For each pair of 40-watt cool white deluxe fluorescent lamps, use a 75-watt frosted tungsten bulb. Your light source should meet the standards specified in ANSI PH2.30-1989, Viewing Conditions—Color Prints, Transparencies, and Photomechanical Reproductions.

For consistency, labs should always evaluate print quality under the same type of lighting conditions that will be used for print viewing and display.

Effects of Storage Conditions

When kept under refrigerated conditions (13°C [55°F] or lower), this paper can age for 18 months and still be within limits for hue. As unexposed, unprocessed paper ages, its hue moves in a green direction.

Room-temperature storage will accelerate the aging effect, and will cause a change in hue. After three months at room temperature, the hue will be about halfway to the limit, but prints made on the paper will still be acceptable. After six months at room temperature, the hue will be close to the limit, and you will notice a hue in prints.

Effects of Processing Problems

Severe developer oxidation or low processor utilization will produce a slightly pink (magenta) hue in images on EKTAMAX RA Paper. Extreme contamination of the developer with bleach-fix will produce a green hue shift and a green D-min. In most cases, a process condition that causes a noticeable hue shift will also yield unacceptable results with KODAK PROFESSIONAL PORTRA, SUPRA, and ULTRA Papers, and will be evident in control-strip plots.

The one condition that process controls strips do not show very well is the formation of leuco cyan dye. With color papers, a slight level of leuco cyan dye can be tolerated in prints, and will show up in the control plots to a very limited degree. However, even low levels of leuco cyan dye can cause a red hue in images on EKTAMAX RA Paper.

The following section, “Process Troubleshooting,” describes ways to avoid and correct process problems that cause a hue shift in EKTAMAX RA Paper.

PROCESS TROUBLESHOOTING

Images on EKTAMAX RA Professional Paper that have a noticeable hue may indicate that your process has a developer or a bleach-fix problem.

Important

Before making any changes to your process, be sure that you are using the appropriate light source to view the prints. An apparent hue shift may be related to viewing conditions.

Identifying the Problem

Follow the steps below to identify the cause of a hue shift:

	1. Check for high developer activity (e.g.,
If the image		high replenishment rate, high temperature,
If the image		contamination of the developer by
tone is cold		bleach-fix, etc.)
		bleach-fix, etc.)
	2.	Check control plots.

	1. Check for leuco cyan dye (follow
		procedure outlined below); if none is
If the image		present, proceed to Step 2. If leuco cyan
tone is warm		dye is present, see “Leuco cyan dye/low
		bleach-fix pH.”
	2. Identify the image tone as pink or red.


	a. Check for low developer activity (e.g., low
		utilization, low replenishment, high
If the image		oxidation, etc.); if none is present,
tone is pink		proceed to Step b.
(magenta)*	b. Check for excess developer in the
		bleach-fix (excessive carryover or low
		bleach-fix replenishment).

If the image	a. Recheck for leuco cyan dye.
tone is red*	a. Recheck for leuco cyan dye.
tone is red*

*You can use the KODAK Color Print Viewing Filter Kit to differentiate between pink and red. If prints look better through the cyan filter than through the green filter, the hue is red. You can suspect that leuco cyan dye is present.

2	Supplementary Information on KODAK EKTAMAX RA Professional Paper • CIS-144