I think some of the catalogs like Schreiners 'sometimes' depict an iris with more vivid color than real life. I am not accusing them of touch ups, but maybe with their professional photogs, they can capture the best lighting possible.
However, it is only rarely that with my own iris I am disappointed because of a wash out in color. Many times, an iris will bloom and be even more vibrant or radiant than I ever thought it would be.
I think that iris color is dependent on growing conditions. In my opinion (after going to the Fresno Ca convention in 2004) North East grown iris show more vivid coloration. Cold climates intensify depth of color.
I don't know what you can do, as far as additives, to help the situation, but I am just letting you know what my observations are.
Laetitia

You may want to wait and evaluate the blooms over a few seasons before deciding a course of action. I have noticed that some irises look very different after becoming established in a new home over a couple of years. It is possible that the colors will be more in line with their 'normal' tone with a little time. I never trust a first year bloom to be indicative of the overall variety's future performance. If you see the same lack of good tone over several seasons then you may have a mis-marked iris (if it is white when it should be brown) or a nutrient deficiency if the color is there, but not expressing as it should.

Mike

I can second the climate effect. I didn't recognize an iris I've had for 10 years --- a cold spring enriched the colors beautifully.

Owyhee Desert sounds like a mismark. Pink Froth looks like a plicata from 4 pics I've seen (with a very light fall rimmed in the standards' blue-pink color).

Printed catalogs, as mentioned, can be way off on colors. It would be too expensive to produce top quality color printing. AND Pictures on the net can be quite off!! We were treated to pics of iris on the gallery this year by 2 people using Canon Rebels. Whoa. Made my pics look like dog meat.

Lastly a monitor's calibration may be off. And viewing indoors with incandescent lighting is even different from daylight. I often lighten a picture to see how the iris will really appear. Oversaturation in digital pics. is common.

i know temps affects color greatly, the cooler your area, the more vibrant the color. i have been to schreiners many times and not once would a pic not look like what they are growing. cooleys catalog pics look off to me, from their garden and in real life...

Hummmmm, really thanks for the input. Anyone use mag. or something that developes color for them?
Mike I have seen the ones I mentioned bloom for two years and it is sooooooooo true. They seem so much truer the second year.
I forget that something coming into the garden may be miss labeled. But I don't think that is the case here. However when they are almost white with no marking what so ever it would be hard to tell. I think I should just experiment with magnesium and see, will let you all know how it goes.
Would like to hear from some more folks on this color acheaving idea.
Janene

I'd defintely would have to agree with weather conditions and establishment. When I first bought Cajun Rhythm, I was excited to have it, based on the picture I saw in Schreiner's catalogue. However, it's first year in bloom, the blossoms were almost white and no where near the vibrant orange it was supposed to be. When it bloomed again next year, the flower dramatically changed to the actual color as seen in the catalogue.

Carlos
http://www.brightonparkiris.com