[HN Gopher] Lightfastness Testing of Colored Pencils
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Lightfastness Testing of Colored Pencils
Author : picture
Score : 97 points
Date : 2025-07-04 23:15 UTC (2 days ago)
(HTM) web link (sarahrenaeclark.com)
(TXT) w3m dump (sarahrenaeclark.com)
| hoppyhoppy2 wrote:
| https://web.archive.org/web/https://sarahrenaeclark.com/ligh...
| gennarro wrote:
| Very spammy images. Is this a legit resource? The test is
| interesting though 6 hrs/day in sunlight is very extreme for
| artwork.
|
| Also I'm wondering is a fixer would help or hurt the testing.
| This is common with some art, like pastels.
| hoistbypetard wrote:
| What did you find spammy about the images? The ads for the
| artist's coloring books and calendars and such?
| ethan_smith wrote:
| Accelerated testing (6hrs/day) is standard practice in
| materials science - it compresses years of normal exposure into
| months while maintaining relative degradation patterns.
| Fixatives might alter results by adding UV inhibitors, but most
| artists want to know worst-case baseline performance.
| hinterlands wrote:
| Although someone will challenge me on that, I'm 100% sure that
| large chunks of the text are AI-generated. That said, the
| website itself has been around at least since 2017 (the text
| just wasn't as verbose - e.g., https://sarahrenaeclark.com/diy-
| gift-bag/).
|
| So, I suspect it's legit. It's a case of an author leaning on a
| crutch for writing, but we're here to judge the results, not
| the phasing.
| humblebeekeeper wrote:
| Why do you think it's AI? It reads to me like someone who has
| a special interest and a data driven mindset.
|
| I've seen plenty of people "rate every X" in youtube videos
| or blogs before, this one is just more data oriented than
| most.
| hinterlands wrote:
| First, it just reads that way. It's the default style if
| you ask ChatGPT to write a couple of paragraphs that
| explain why lightfastness is important.
|
| Second, while I know there are reasons to be skeptical
| about AI text checkers, the author's earlier (less verbose)
| style doesn't get flagged at all, while the style in more
| recent articles gets classified as heavily AI-assisted.
| humblebeekeeper wrote:
| > First, it just reads that way. It's the default style
| if you ask ChatGPT to write a couple of paragraphs that
| explain why lightfastness is important.
|
| It doesn't read that way to me, and I've read lots of
| ChatGPT text. We've come to opposite conclusions, I'm
| curious what qualities you are identifying/keying off of?
| capnrefsmmat wrote:
| In our studies of ChatGPT's grammatical style
| (https://arxiv.org/abs/2410.16107), it really loves past
| and present participial phrases (2-5x more usage than
| humans). I didn't see any here in a glance through the
| lightfastness section, though I didn't try running the
| whole article through spaCy to check. In any case it
| doesn't trip my mental ChatGPT detector either; it reads
| more like classic SEO writing you'd see all over blogs in
| the 20-teens.
| ezconnect wrote:
| She didn't even promoted a single pencil brand on the
| conclusion. She just shows the data and let the viewers decide.
| humblebeekeeper wrote:
| There's:
|
| 1 header image
|
| 1 image showing in process
|
| 1 image explaining lightfastness
|
| 3 images explaining the importance of lightfastness
|
| 1 image explaining the measurement process
|
| 1 image linking to another article diving much deeper into the
| methodology
|
| 1 image linking to another article on a different color pencil
| concern (layering)
|
| 1 image representing each brand-line's lightfastness
|
| Every single one of those images seemed relevant to the concept
| presented and clarified something that would have been
| difficult to articulate succinctly in writing. For example, the
| "how was this measured" is a lot easier to understand once
| you've seen the grid of squares before and after than it would
| be to try and articulate the fading of colors in small squares
| in text.
|
| There's LOTS of individual images on specific brands, but given
| their wild degree of variance, I think it's really useful to
| perceptually see what's going on with each one.
|
| I'm curious, where do you feel the images were "spammy"? It's a
| conclusion I _heartily_ disagree with, but would love to
| understand.
| hoistbypetard wrote:
| I really enjoyed reading this even though I have no direct
| interest in the lightfastness of the pigments in colored pencils.
|
| It was just fun to see what someone who is deeply invested
| thought important to test, explain and research about something
| I'd have previously called a matter of aesthetic preference (as
| opposed to a thing you can benchmark).
| sunrunner wrote:
| > test, explain and research about something
|
| There's more high quality engineering discipline in this 'non-
| engineering' article than in seemingly a lot of self-professed
| software engineering today ;)
| ChrisMarshallNY wrote:
| Heh. As a [former][0] artist (and musician), and an engineer,
| I can confirm that the Venn diagrams overlap, quite a bit.
|
| Pigment color is a real heavy-duty field. There's a guy named
| Michael Wilcox[1] that is famous for his work on pigment
| color.
|
| [0] https://news.ycombinator.com/item?id=40917886
|
| [1] https://michaelwilcoxschoolofcolour.com/about-michael-
| wilcox... (Has an annoying popup on every page).
| sllabres wrote:
| What a effort. I did something similar for some pens and
| different inkjet colors a long time ago, but not nearly as broad
| or as methodical. The inkjet inks (especially red) were already
| blown after a short time (>4 months). But black still holds up 20
| years later till now, only a little bit faded, so one can see the
| tracks of each row.
|
| Foils (laminate or adhesive foils) or protective spray (UV) did
| not change the result at all. But one film tore and gave the
| whole thing an interesting, crackle-like appearance. However, the
| colors all faded in the same way, whatever protective used
| compared to direct exposure to sunlight.
| andrewla wrote:
| I've noticed this as well -- at one point I had switched from
| Canon inkjet refills to a generic third party refills, and
| years later the photos from the knockoff have faded to an
| astonishing degree while the Canon ink prints look bright and
| vibrant.
|
| Going through old photo albums that my parents have show a lot
| of fading as well, even though the pictures themselves were
| kept in photo albums in the dark for many years. We have
| negatives for some of those photos, which when scanned are
| bright and vibrant, but the prints vary significantly.
| dylan604 wrote:
| uh-oh, did you just anecdotally confirm that buying first
| party inks is the better decision? careful, you might just
| confirm to the makers that their DRM policies are legit.
| codazoda wrote:
| Crazy amount of effort here. Awesome.
|
| I did this for a single color from a single printer--the black
| toner from my Brother laser printer. I left it in my West
| facing office window for about 18 months. On the BACK SIDE I
| labeled it with pen. The pen on the back faded to almost
| nothing but the toner did not fade at all.
|
| I did not do monthly scans, that would have been a better
| "experiment", but I was satisfied that a B&W laser print would
| last a very long time.
|
| Maybe I should lightfast test my Brother Laser and my HP Inkjet
| (with Black Pigment based ink).
|
| I thought that pigment based inks would be both waterproof and
| lightfast. Since I started to airbrush watercolor over my HP
| prints I am now very aware that these pigment based inks are
| not waterproof, even after long drying times.
| wrp wrote:
| I did this for colored mechanical pencil leads. Short answer, use
| the Staedtler Mars Micro Color if you need lightfastness.
| dylan604 wrote:
| It's interesting how pink tends to be the worst of the colors
| according to the charts. I wonder what it really looks like on
| paper. Does it disappear completely so it is very hard to see, or
| is it just invisible in the data as it rounds to 0 but leaves
| something visible on the paper? If you did an image in pink
| duotone with the worst offenders, would you have a blank sheet of
| paper after 26 weeks? Or does it look like something done in
| white duotone?
| ChrisMarshallNY wrote:
| Red, in general, sucks.
|
| Look at all the red-white-and-blue bumper stickers. They are
| usually white-and-blue.
|
| Around here, we have school buses with a sticker on the back,
| announcing that they don't turn right on RED (with "RED" being
| in heavy letters, and colored red).
|
| They frequently say that they don't turn right on.
| humblebeekeeper wrote:
| As someone who is heavily tattooed, I'd LOVE to see this analysis
| for tattoo inks.
|
| Fun fact: UV light makes tattoo particles smaller, which makes
| them easier for your lymphatic system to carry them to your lymph
| nodes. The particles are easy to transport into the lymph nodes,
| but difficult for your body to remove from your lymph nodes,
| meaning that for heavily tattooed people like myself, surgeries
| can be a potentially very colorful endeavor! (Or, if you have
| primarily black tattoos, it can be a spooky endeavor, I suppose.)
| smokel wrote:
| I did similar testing with ball-point pens. Eventually I ran into
| the ISO 12757-2 standard on archival ink, thinking that it would
| be a great idea to use such pens for my intricate drawings.
|
| Turns out the drawings, some of which I actually sold, faded into
| oblivion within about a year. After slightly more careful reading
| of the actual standard, I learned that the drawings were supposed
| to be _archived_ , i.e. kept in a box or a drawer, and not to be
| framed for full-time viewing pleasure.
|
| The typical blue ink in the famous BIC ball-point pens (i.e. non-
| ISO 12757) turns black after some time of sunlight exposure,
| which seems fine.
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