Home Forums Explore Media Oil Painting The Technical Forum Lightfast Confusion

Viewing 15 posts - 1 through 15 (of 121 total)
  • Author
    Posts
  • #993572

    There is a great deal of confusing statements written about many pigments related to lightfastness. We are seeing ratings all over the place. Some places are more direct than others. Today I am doing research for several yellows that have been suggested. I found this information which clearly is the fancy talk around “use at your own risk”.

    Permanence
    Benzimidazolone Yellow has excellent lightfastness and durability. This has made it an extremely important pigment in the printing industry, for applications where lightfastness is a primary consideration. Though it is not absolutely lightfast, it ranks extremely well among organic yellows.
    How could these pigment notations be written better to make us more confident in our choices?

    I am not mentioning the site I found this on or the brand…slamming a brand or site isn’t helping anyone…the object here is how to improve communications between manufactures and artist.

    Thanks to everyone who decides to join in.

    Angel :angel:
    Website Makeover Coming! This is available now.
    http://www.artist-bythesea.com/

    #1242593

    There is a great deal of confusing statements written about many pigments related to lightfastness. We are seeing ratings all over the place. Some places are more direct than others. Today I am doing research for several yellows that have been suggested. I found this information which clearly is the fancy talk around “use at your own risk”.

    [B]Permanence
    Benzimidazolone Yellow has excellent lightfastness and durability. This has made it an extremely important pigment in the printing industry, for applications where lightfastness is a primary consideration. Though it is not absolutely lightfast, it ranks extremely well among organic yellows.[B][/B]

    How could these pigment notations be written better to make us more confident in our choices? I understand there are variables in pigments, but
    the example above leaves me asking…”maybe or maybe NOT”? There are other examples of some statements that are much more confusing…so what
    is an artist to do?

    I am not mentioning the site I found this on or the brand…slamming a brand or site isn’t helping anyone…the object here is how to improve communications between manufactures and artist.

    Thanks to everyone who decides to join in.

    I have been continuing to read and found that there are some brands that are clearer about lightfast. I find that to be more helpful when I am making a choice. I found numerous references to the “automotive” industry. Just for the record that doesn’t inspire me with confidence about the lightfast properties related to artist paints. That is just my view coming from experience in the automotive racing industry. There is much more than just pigment in this equation.

    Given that there are printing pigments that are archival for 100 years or more I can see in some cases that “might” relate. What additives might be added to make them archival is something we wouldn’t know about.

    Sorry about reposting this, but there was a glitch in my original post.

    Angel :angel:
    Website Makeover Coming! This is available now.
    http://www.artist-bythesea.com/

    #1242594

    I found a great link to a site by “WhereFishSing” by Fiona. This pigment/paint list is clear and to the point. Fiona list her credits on the last page. This is an example of a quick reference while deciding on colors. Should there be an assessment that differs from hers, I am sure she wouldn’t mind a nice e-mail with information. It is very kind of her to do this work and offer it for FREE on the internet.

    http://wherefishsing.com/stuff/OilPaintPigmentChart.pdf

    Angel :angel:
    Website Makeover Coming! This is available now.
    http://www.artist-bythesea.com/

    #1242625
    Michael Lion
    Default

        Benzimidazolone Yellow is said to be more lightfast than the common and less expensive PY74.

        PY74 is only an ASTM II lightfastness in tints, while Benzimidzalone is ASTM I in tints.

        The best deal in yellow is LeFranc Yellow by L&B which is a very affordable price and uses bismuth vanadate which is the most lightfast and permanent bright yellow. (Although I wonder why it’s so inexpensive when other brands charge cadmium-level prices for bismuth vanadate yellow.)

        #1242518
        Mythrill
        Default

            Benzimidazolone Yellow is said to be more lightfast than the common and less expensive PY74.

            PY74 is only an ASTM II lightfastness in tints, while Benzimidzalone is ASTM I in tints.

            The best deal in yellow is LeFranc Yellow by L&B which is a very affordable price and uses bismuth vanadate which is the most lightfast and permanent bright yellow. (Although I wonder why it’s so inexpensive when other brands charge cadmium-level prices for bismuth vanadate yellow.)

            It depends on the PY 74. Some varieties are opaque, and these are very lightfast, reaching LF I.

            #1242519
            Mythrill
            Default

                I have been continuing to read and found that there are some brands that are clearer about lightfast. I find that to be more helpful when I am making a choice. I found numerous references to the “automotive” industry. Just for the record that doesn’t inspire me with confidence about the lightfast properties related to artist paints. That is just my view coming from experience in the automotive racing industry. There is much more than just pigment in this equation.

                Given that there are printing pigments that are archival for 100 years or more I can see in some cases that “might” relate. What additives might be added to make them archival is something we wouldn’t know about.

                Sorry about reposting this, but there was a glitch in my original post.

                Seaside, it’s what we discussed before: organic pigments vary much more in quality than their mineral counterparts. If you buy Ultramarine Blue (PB 29), for example, as long as itis pure Ultramarine Blue, the lightfastness should be nearly uniform in all brands.

                But not so with organic pigments. They are made in many different ways, and how they are made affects their lightfastness. This is precisely why Quinacridone Magenta (PR 122) was rated just as LF III-IV (fair-poor) back in the 1990s, but reach LF I (excellent today). Or how the bluish shades of Dioxazine Purple (PV 23) reach LF I in some brands. Some pigments have overall higher quality on the average than others (poor varieties of Quinacridone Rose, PV 19-gamma, are more frequent than poorer varieties of Quinacridone Magenta, PR 122).

                In a nutshell, depending on how it is made, and its average quality the lightfastness of Benzimidazolone can vary from excellent to poor. If you don’t want to risk it, you should get it from a paint brand that is known to have a good variety of that particular pigment (just because they have a good variety of a particular pigment, doesn’t mean all organic pigments will be high quality. You have to check each one individually).

                #1242626
                Michael Lion
                Default

                    It depends on the PY 74. Some varieties are opaque, and these are very lightfast, reaching LF I.

                    All artists paints manufacturers are using versions of PY 74 that have an ASTM I rating. But this pigment is still known to be less lightfast in tints.

                    On the other hand, cadmium yellow also has a question mark.

                    I think that both pigments can be trusted for general use in paintings and you can assume that there won’t be any fading for at least 100 years. To be cautious, you might want to avoid using PY 74 in pale tints. I’d recommend PBr24 (what Winsor & Newton calls Naples Yellow Deep) for pale tints.

                    And I recommend bismuth vanadate, even though it’s a new pigment and some people think it has question marks also.

                    #1242627
                    Michael Lion
                    Default

                        This is precisely why Quinacridone Magenta (PR 122) was rated just as LF III-IV (fair-poor) back in the 1990s, but reach LF I (excellent today).

                        The same has applied to some mineral pigments. Original cadmium yellow was fugitive. Once they learned how to make it so it forms into a crystal lattice which stabilizes it, it became more permanent.

                        #1242520
                        Mythrill
                        Default

                            The same has applied to some mineral pigments. Original cadmium yellow was fugitive. Once they learned how to make it so it forms into a crystal lattice which stabilizes it, it became more permanent.

                            It’s not that it was fugitive, since fugitive means a pigment depends only on light to fade (like Alizarin Crimson, PR 83). Instead, it was more reactive, meaning it was particularly vulnerable to fading when mixed with other paints such as Chrome Yellow (PY 41), which Van Gogh happily used. In other words, it won’t fade unless certain conditions are met. With newer cadmiums, these conditions are a bit harder to meet (as you said, they are more stable). Plus, other pigments used today in the palette are far less reactive than the ones we used to use. Just look at phthalos, for example, or Chrome Titanate (PBr 24) and Nickel Titanate (PY 53). They won’t react with ANY color common to your artists’ palettes.

                            #1242628
                            Michael Lion
                            Default

                                It’s not that it was fugitive, since fugitive means a pigment depends only on light to fade (like Alizarin Crimson, PR 83). Instead, it was more [B][I]reactive[/I][/B], meaning it was particularly vulnerable to fading when mixed with other paints such as Chrome Yellow (PY 41), which Van Gogh happily used. In other words, it won’t fade unless certain conditions are met. With newer cadmiums, these conditions are a bit harder to meet (as you said, they are more [I][B]stable[/B][/I]). Plus, other pigments used today in the palette are far less reactive than the ones we used to use. Just look at phthalos, for example, or Chrome Titanate (PBr 24) and Nickel Titanate (PY 53). They won’t react with ANY color common to your artists’ palettes.

                                Wikipedia says: “Fugitive pigments[FONT=sans-serif] are [/FONT]impermanent pigments[FONT=sans-serif] that lighten, darken, or otherwise change in appearance or physicality over time when exposed to certain environmental conditions, such as light or pollution”

                                Under that definition, fading because of exposure to ambient humidity would make a pigment fugitive.
                                [/FONT]

                                #1242521
                                Mythrill
                                Default

                                    Wikipedia says: “[B]Fugitive pigments[/B][COLOR=#252525][FONT=sans-serif] are [/FONT][/COLOR][URL=https://en.wiktionary.org/wiki/impermanent]impermanent[/URL][URL=https://en.wikipedia.org/wiki/Pigment] pigments[/URL][COLOR=#252525][FONT=sans-serif] that lighten, darken, or otherwise change in appearance or physicality over time when exposed to certain environmental conditions, such as light or pollution”

                                    Under that definition, fading because of exposure to ambient humidity would make a pigment fugitive.
                                    [/FONT][/COLOR]

                                    Ah, now that you mention it, I see.

                                    I prefer to draw a line, because if you consider everything a pigment may be exposed to, no pigment is really permanent. We have Ultramarine Blue (PB 29), for example, standing intact for 3,000 years under the desert – but expose it to lemon juice, and it fades immediately. So, I draw the line by separating pigment permanence by each type of damage, the most common being light damage (fading). Not considering this would make us classify pigments such as Vermillion (PR 106) as fugitive (it blacks when exposed to hydrogen sulphide), when it is considered permanent.

                                    In the case of cadmiums, they need to reach a certain threshold of humidity and light to fade. There used to be days here in my state in which the air would hit 100% humidity, and I’m sure that if cadmiums were expoded to light in these conditions, they would fade. However, reaching those conditions simultaneously is quite rare. When talking about indoor paintings, if it’s damp enough for cadmiums to be prone to fading, it’s not bright enough, as the dampness in the air is usually caused by heavy rain.

                                    #1242629
                                    Michael Lion
                                    Default

                                        “Fugitive” just means the opposite of “permanent.” There are obviously various degrees of each. If a pigment can last for 50 years if the painting is kept indoors, without noticeable change in color, then it’s generally considered to be “permanent,” at least the way that Winsor & Newton uses that word.

                                        Lightfastness is one element of permanence. As you say ultramarine is very lightfast, but can be impermanent because of chemical reactions. However, since one can expect that there won’t be any noticeable change in 50 years if painting is kept indoors, ultramarine can be considered permanent.

                                        In another thread, I coined the word “ultra-permanent” for pigments that won’t have any noticeable change in color for at least 500 years. Ultramarine and cadmium definitely do not fall into that category.

                                        #1242550
                                        Anonymous

                                            If a pigment can last for 50 years if the painting is kept indoors, without noticeable change in color, then it’s generally considered to be “permanent,”

                                            I and many others have numerous paintings done 50 yrs ago that used PR83 Alizarin Crimson and they easily do fit this criterion of being permanent. :clap:

                                            #1242630
                                            Michael Lion
                                            Default

                                                I and many others have numerous paintings done 50 yrs ago that used PR83 Alizarin Crimson and they easily do fit this criterion of being permanent. :clap:

                                                Are you completely sure that if you could go back in time and compare, side by side, the fresh painting vs the 50-year-old painting, that you wouldn’t notice a difference?

                                                I think you are using the same reasoning here as with the “linseed oil based white doesn’t yellow” argument. Just because you don’t perceive the fading doesn’t mean it hasn’t happened.

                                                (In my sample that’s less than a month old, I can now readily see that the Grumbacher linseed “white” is more yellow than the Winsor & Newton safflower white.)

                                                #1242551
                                                Anonymous

                                                    If the AC chroma was screaming any more than it is now then I would give them to a Bob Ross fan cause they would be too gawdy for me to stand.
                                                    Same thing with the whites in my snow scenes, if they were any whiter I would have to wear sunglasses to look at them.
                                                    I do not say that linseed oil whites do not yellow, I have posted tests here for years that demonstrate yellowing of linseed whites, walnut whites, etc.
                                                    I have said that when used in normal painting contexts and given ample light exposure, that the yellowing has never ever been significant.
                                                    Robert Gamblin, Virgil Elliott, and many other experts have also said this too.

                                                  Viewing 15 posts - 1 through 15 (of 121 total)
                                                  • The topic ‘Lightfast Confusion’ is closed to new replies.