It's summer, and the sun is getting stronger.
Regarding leather products, we sometimes receive questions like, "Can I sunbathe leather to speed up its aging?" This method involves intentionally exposing new leather to sunlight to accelerate color changes.
Indeed, UV rays are one factor that promotes leather aging. However, Munekawa does not recommend intentionally exposing leather to strong sunlight for extended periods. From a long-term perspective, we believe the risk of shortening the leather's lifespan outweighs the benefits.
Why Munekawa Does Not Recommend Sunbathing Leather
Sunbathing, a method where new leather is exposed to the sun for a while to deepen its color or accelerate changes due to tanning, is sometimes introduced on websites and elsewhere.
Certainly, exposing leather to sunlight can accelerate aging. However, from our perspective as craftsmen, we believe there are few benefits to intentionally exposing leather to the sun.
There are two main reasons for this:
- Increased drying, leading to a higher risk of cracking
- Color fading and discoloration due to UV rays
When leather is continuously exposed to strong sunlight, it dries out, losing moisture and oils, and becoming stiff. If used in this state, it can lead to cracking at folds and corners.
Furthermore, UV rays can cause leather colors to fade. This effect is particularly significant for colored leather, potentially ruining its vibrant hue.
While the color does change, depending on the leather color, it might look faded and not achieve the desired aging effect.
How Leather Changes When Exposed to Light
A clear example is sample products displayed for a long time in department stores or shops. Leather products constantly exposed to artificial lighting will gradually take on a brownish tint, regardless of their original color, if they are vegetable-tanned.
Vegetable-tanned leather, such as Buttero, changes color when exposed to light because the tannins in the leather react to UV rays. The same reason explains why natural leather turns an amber color.
Since such changes occur even under artificial lighting, the effect will be even stronger under more intense sunlight.
While UV rays are indeed a factor in aging, it's best to consider that excessive exposure to light will likely lead to greater disadvantages.
Sunburn and Aging: Similar but Different
You might think, "If sunlight is one factor in aging, isn't sunbathing a shortcut to aging?"
However, beautiful leather aging is not just due to light; it's a gradual process that naturally occurs over a long period, influenced by a combination of factors such as hand oils, small scratches and friction from use, air, and humidity.
While sunbathing does change the color, it only receives the effects of light and dryness, so it won't achieve the moist luster or supple feel of well-used leather. The color of long-displayed samples deepens, but their appearance differs from leather that has been cherished and used over time.
Our belief is that beautiful leather aging comes from the accumulation of daily use, and that's precisely why leather products used for a long time are so valuable.
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Light Through a Curtain is Enough
Nevertheless, some people may still want to "quickly settle the color of new leather" or "experience a change."
In that case, instead of direct sunlight, it's best to expose it to indirect light through a curtain for a short period. Even light through a curtain is sufficient to notice changes in the leather's color.
If you attempt sunbathing with direct sunlight, please do so at your own risk, understanding the risks of cracking due to drying and color fading. Also, avoid long exposure, wipe it dry afterward, and replenish oils with a care cream if dryness is a concern.
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Tips for Protecting Leather Goods from Summer Sun
Beyond intentional sunbathing, summer is a season when leather is easily exposed to sunlight in daily life. Even by being mindful of the following three points, you can reduce the burden on your leather:
- Do not leave items in direct sunlight, such as by a window or inside a car.
- If wet, do not dry in the sun; allow it to air dry naturally in a well-ventilated, shaded area.
- If dryness is a concern, wipe it with a dry cloth or use care cream to replenish oils.
Especially in summer, car interiors can get very hot, which can cause drying and deformation. Even for short outings, try to make it a habit to take your wallet and key case with you out of the car.
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Summary
While exposing leather to sunlight certainly changes its color, considering the risks of cracking due to dryness and color fading, our honest opinion as craftsmen is that we do not recommend intentionally exposing it to strong sunlight for extended periods.
If you continue to use your leather without overdoing it, you'll suddenly notice it has developed a wonderful character one day. Enjoying this process is what Munekawa recommends most.
If you have any other concerns about leather tanning, drying, or daily care, please feel free to contact us at our directly managed store or online store.
▶︎ Details of Munekawa's directly managed store in Daikokucho, Osaka, here
