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Inkjet B&W prints:

colour casts

Q

I want to print photographs in

B&W/greyscale without getting

a green or magenta colour cast.

I’ve literally spent days researching this

subject (via Google and many forums)

and I still have no definitive answer,

save for spending over $1,000 on a new

printer. I’m currently using an Epson

Artisan 1430 (A3+ printer with six ink

tanks). Also, I have just installed a brand

new Epson Stylus Photo T50 (six ink

tanks - only one black) and it prints my

B&W pics with a magenta tinge. I’m

using genuine Epson Inks & Epson

gloss paper. Can I achieve my objective

without forking out maximum dollars?

Ernie Goulding, Nelson Bay, NSW.

A

Thanks for sending two samples

of images converted from colour

to greyscale in Corel PaintShop

Pro, as well as the high quality scan

of an old B&W film print. Both of the

monochrome conversions show a good

range of tones in the greyscale, while

the flatbed scan contains an unexpected

content from the Blue channel of the

scanner, particularly in the shadows.

(Likely, the scanner requires calibration

against an IT 8.7 Scanner Calibration

Target – see http://www.targets.coloraid.de ).

This confirms that we can concentrate

our attention and efforts on the printers

as being the source of the colour casts.

Presumably, you’ve already loaded the

appropriate software driver supplied by

Epson for the printer, and ICC printing

profile for the paper you are using. Your

experience of a green colour cast (for

the Epson 1430), and a magenta colour

cast (for the Epson T50) is very familiar

to a large number of photographers

attempting to print good quality B&W

using inkjets from any manufacturer. It’s

worth noting that green and magenta are

complementary (opposite) colours. Even

if you brought your image files to a photo

lab or photo kiosk, there’s the likelihood

that these, too, would exhibit a colour cast,

depending on the workf low deployed, such

as an operator manually intervening to

ensure that a calibrated, well-maintained

B&W “channel” is selected to produce the

best print.

Inkjet printers intended for producing

accurate B&W prints have multiple

cartridges with varying shades of black/

grey. Higher-end models are capable of

producing better results more readily, as

regards to neutrality, etc. Space does not

permit going into all the intricacies of

inkjet printing theory and practice (which

are very involved!). In any case, clearly

you’ve already invested a lot of effort

and money into your setup. Presumably

your end goal is to be able to produce

exhibition-grade prints for display and/

or judging at photographic competitions.

This will likely be indoors, in relatively

bright incandescent (tungsten?) lighting.

Note that due to the specific inks

and/or their mixing, the colour cast of

your prints can appear different under

varying lighting conditions, such as a

green cast when viewing with daylight,

and/or magenta cast under f luorescent

or tungsten lighting. Being aware of

the “metamerism” exhibited by inks

(metamerism can cause colours that

look fine in one light to look strange

in another) will help you make better

decisions when looking for or correcting

the colour cast. Also, it’s likely your glossy

photo paper is exacerbating the effects

of metamerism. Optical Brightening

Agents (OBAs) present within the paper

can also create havoc under varying

lighting conditions. Have you previously

tested other paper types, like warm-toned

14 AUSTRALIANPHOTOGRAPHY.COM

QUESTIONS & ANSWERS

AUSTRALIAN PHOTOGRAPHY + DIGITAL JULY 2015

Prashphutita

A. Greco AP answers your

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