MITRA Forum Question Details

ApproveRejectUn-ApproveWondering if living in a very hot climate, as you noted, as well as assuming low humidity, has impacted the feel of the pastels by pulling out any of the normally retained moisture from the clays and chalks that are integral to pastel formulations. Not to mention the clay component of such pigments as ochres. All those materials are hygroscopic and would readily absorb moisture until reaching equilibrium with the relative humidity of the environment. I would imagine, in that scenario, a chalk pastel in a higher humidity could have a smoother, creamier feel - versus a drier, scratchy one in low humidity. If this is the culprit, you might try storing them in a space where you can control the humidity and keep it within a range of 40-60%? Keep in mind this is my own speculation only and as Kristin states, pastel experts might be able to add to the insights and causes.

Sarah Sands
Senior Technical Specialist
Golden Artist Colors

ApproveRejectUn-Approve20 years isn't that old. I have many 45-50 years old and they are still in great shape. Perhaps since yours absorbed so much moisture as they were in a humid climate, the binder may have migrated to the surface and got blotted out, weakening the pastel.Pigment would not change, but let's say a mold or fungus entered the humid pastel it might appear chalky.

ApproveRejectUn-ApproveThey traveled with me from humid Central America, extremely humid and hot Asia the extremely dry and hot Middle East and then on to extremely hot and often humid East and West Africa. Sorry for my poorly written question. Some of them are rather dry (actually the softer pastels). Thank you.

ApproveRejectUn-ApproveThank you all. Very helpful and will try to rehumidify them (not a real word). The thought about mold sounds very possible. That too I will check out.

ApproveRejectUn-ApproveWith that many pastels you have a pretty valuable stock. I have ground up old broken pastels before, adding distilled water until it forms a smooth paste, then shaped them into sticks which were left out to dry fully. As long as you don't mix hard pastel sticks with soft pastels in the "re-manufacturing" process, they work quite well. You might try doing that with a few of the worst case sticks. If you want to harden the final stick you can add varied amounts of binders such as clay.

I wear nytrile gloves during the process and just roll them in my palms to the desired thickness. You can then use some parchment paper or waxed paper to make them square if you want by flattening the rolled sticks with a piece of board on either side of the waxed paper. Reminiscent of working with Play Dough as a kid.

You will run into issues if you mix hard sand soft sticks - there will be harder chunks mixed in with the softer matrix.

ApproveRejectUn-ApproveAfter my last comment about grinding them with water to rework the sticks, I realized that nowhere in any of the posts was it stated, nor was the question asked - if they are oil pastels or regular hard / soft pastels. I assumed they were regular chalk type pastels not oil pastels with my response.