Making a Blue Sherlock

@cow-mow asked how my Blue Sherlocks were made. The process is called cyanotype. I use paper pre-prepared with a photosensitive solution of potassium ferricyanide and ferric ammonium citrate. To make the image, I used one of my old drypoint etching plates. But it also works with plants or flat items with an interesting silhouette, or even with slides or photo negatives.
1. The items are placed on the photosensitive paper, which is then exposed to sunlight. With full sun, a few minutes suffice.
2. The formerly blue paper turns almost white because of a chemical reaction (reduction) of the iron.
3. Then the items are removed. A silhouette of the parts where the UV-rays didn’t reach is visible. It’s not stable, however.
4. To fix the image, the paper is rinsed with cold tap-water. The water washes away the formerly blocked out parts where the ferric solution hasn’t been fixed to the paper by sunlight. They appear as a white negative print of the original image or items.
5. While the surrounding paper looks turquoise at first, over the course of a few hours, the colour changes to Prussian Blue (ferric ferrocyanide) which is stable under sunlight and no longer soluble in water.

If you like the Blue Sherlock, the one shown here and five more are still availabe at my storenvy for $5 each with free shipping.

Sherlockchallenge: Drip


“That strange smell is even stronger in here, don’t you think? It’s … I don’t know. It’s familiar, but definitely not the stolen perfume we’re looking for. It almost smells like—”

“Disinfectant. Indeed, John, because that’s what it is. Point your torch up there. So, no counterfeit perfume or the Class A drugs, but I think we’ve uncovered a far more heinous crime.”

“Yeah, the arseholes have been hoarding disinfectant, probably to sell for huge profits to hospitals that’ve run out.”

“It’s even worse, I fear.”

“Worse than profiteering on hospital essentials during a pandemic?”

“Yes. There’s toilet paper up there, too.”

“Bloody wankers.”

For this month’s @sherlockchallenge​ : Drip

DIY face masks

How to Make a Face Mask for Hospitals and Medical Centers

Hospitals and medical centers across the country are asking sewers to make face masks to protect out health workers. You can google “how to sew face masks for hospitals” to find out where fabric masks are being requested.

Stillwater Medical Center is asking sewers to follow the face mask pattern from here.

From Deaconess Health System:

EVANSVILLE, Ind. — Citing shortages, Deaconess Health System, including Henderson’s Methodist Health, has asked the public to sew face masks for staff fighting coronavirus.

“This does follow CDC protocols that you can find on their website that if all other supplies are not available, that handmade masks that meet certain criteria are acceptable,” Deaconess spokeswoman Becca Scott said.


The release with the video, pattern and instructions was posted to the Deaconess Facebook page Thursday morning and is available at A PDF of the pattern is available here and embedded at the bottom of this article.


Deaconess has “a sample video” about how to make the masks, which Scott said will be sterilized when they come in.


From Forbes here:

Additional Resources for Open Source or Volunteer COVID-19 Projects:

One of my favorite how-to sites is Instructables. The DIY Cloth Face Mask has almost 100,000 views. It is a step-by-step instruction for those who need it. Kudos to ashevillejm.

In 2006, CDC released a Simple Respiratory Mask design using heavyweight t-shirts in its Emerging Infectious Diseases journal. More of an academic post, but some ideas in it.


A Facebook group was formed last week: Open Source COVID19 Medical Supplies. It is worth a visit — in just a few short days there are 20,000-plus members and volunteers.

If you are looking for some research and street-level testing of various materials for DIY mask-making, this post from Smart Air Filters is exceptional: What Are The Best Materials for Making DIY Masks? It also includes a few great links at the end of it.

Introducing the Medieval Ass

Apart from corresponding with my students via email, I spent most of yesterday drawing donkeys. This animation is for a new publication by University of Wales Press: Introducing the Medieval Ass. I also illustrated their book Introducing the Medieval Dragon which features a flip-book animation of a flying dragon.