With bromide papers, gold toners produce virtually no color shift, though they do increase density. These color shifts can be desireable under certain circumstances, but many people don t find them particularly pleasing. Judging from IPI s test results, unless the entire image were thoroughly toned, the only truly archival gold toners would be those based on thiourea, and the results might or might not be aesthetically pleasing. Platinum is rarely used as a toner today, due to its expense. Luis Nadeau notes that experiments performed by Ilford in the 1970 s with a very old platinum toner formula caused image destabilization, but he was unable to provide details as to the exact toner formula or the exact problems encountered.
Selenium is the most popular toner among fine art photographers.
It converts silver to silver selenide, and causes a color shift with most papers, ranging from purple with bromide papers to reddish-brown with chloride papers, which many people find quite pleasing. Untoned portions of the image may be subject to future deterioration. This flies in the face of longstanding advice from Kodak which, as repeated by Ansel Adams and many others, said that selenium provides protection even in very high dilutions which do not cause color changes. He is very skeptical as to the efficacy of archival print washers. Kodak Polytoner, which contains both selenium and sulfide, is probably more effective than selenium toner alone for archival purposes, but I personally have never been able to obtain precisely the tones I desire from it.