Why pictures yellow and how to prevent it
Yellowing is rarely a fault of the work — it is usually a fault of the framing. Three causes I run into on most older commissions when I remount them.
Three quiet enemies
Most pictures that come to me for remounting have the same three problems: acidic materials in contact with the work, long-term UV exposure and condensation inside the frame.
Each of them works slowly but relentlessly. After ten years you cannot tell. After thirty the work is unrecognisable.
Acidic materials
Ordinary card, greyboard, a chipboard backing — all of it releases acids. They migrate into the paper of the work and cause browning, brittleness and staining. On photographs they also break down the gelatin layer.
The fix is trivial: an acid-free mat (pH 8–9), archival board at the back, archival tapes and corners. It costs a few crowns more and saves the work for decades.
UV radiation
Sunlight destroys pigments, organic dyes and paper alike. Watercolours and photographs are the most sensitive — without UV protection they fade visibly within 5–10 years.
If your picture faces a window or sits under a halogen, UV glass is not a luxury, it is a necessity. UV70 is enough for residential conditions; UV99 suits institutions or works in harsh direct light.
Condensation and moisture
When paper touches the glass directly, moisture condenses on it. Over the years this produces stains, tidemarks and local fading. A mat prevents it — it holds the work a few millimetres off the glass and lets air circulate.
For pictures hanging in bathrooms or kitchens I also recommend a dehumidifier sachet inside the frame — a small pack that absorbs moisture and lasts 3–5 years.
What to do about it
If you have an older piece that is starting to yellow or stain, remounting helps. We open the frame, carefully clean the work, replace every material with archival ones and return it to a new frame (or keep the original one where that makes sense).
At the workshop in Přísečná I look at it free of charge — come by, show me, and I will tell you straight away whether it can still be saved and what it will cost.
Marek Homolka
Third-generation framer · RDH Rámy, Přísečná
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