Why Does Gel Polish Change Color in the Sun? Purple Marks and Reflective Gel Polishes
Blue-purple marks on gel polish or Top Coat are among the effects that can surprise not only clients, but sometimes even experienced nail technicians. In direct sunlight, blue-purple patches may appear especially on dark or nude shades and then gradually disappear within a few minutes after moving indoors.
In this situation, it is natural to wonder whether the material is faulty, whether there was an application mistake or whether the product was insufficiently cured in a UV/LED lamp. In most cases, however, this is a natural optical effect related to the composition of the material, the intensity of sunlight and the way the individual layers have been applied.
Nail technicians also frequently discuss the gradual lightening of some Reflective gel polishes, for example after a summer holiday. Although both effects are connected with sunlight, they do not have the same cause.
In this article, we explain why these changes occur, how their occurrence can be reduced and when they are simply a normal property of the material.
What causes purple marks on gel polish?
Modern UV/LED materials are expected to meet much higher demands than simply creating a strong and glossy surface. They are also expected to provide long-term color stability, resistance to normal wear and support the protection of pigments against the effects of sunlight.
For this reason, manufacturers use various stabilizing ingredients in some Top Coats and no-wipe gel polishes, such as UV absorbers or optical brighteners. These substances help slow the natural aging of the material and contribute to maintaining the original appearance of the manicure for as long as possible.
Under certain conditions, however, some of these components may create a subtle blue-purple optical effect when exposed to very intense sunlight.
In most cases, this is neither a chemical change in the material nor damage to it. What changes is primarily the way light passes through the individual layers of the nail enhancement.
This is also why the effect is usually temporary. Once the client moves into the shade or indoors, the blue-purple tint gradually becomes weaker or disappears completely.
Why are purple marks not visible across the entire nail?
One of the most common questions is: “If it is a property of the Top Coat, why does the whole nail not turn equally purple?”
The answer is mainly connected with the thickness of the individual layers.
Ideally, the layers of base, colored gel polish and Top Coat would be perfectly even across the entire nail surface. In practice, however, small differences almost always occur.
A slight unevenness in the base layer, a fine mark left by a nail file, a locally thicker color layer or slight pooling of the Top Coat can be enough. In these areas, light passes through a thicker polymer layer, which can make the optical effect more visible.
This does not mean that one part of the nail contains more UV-stabilizing ingredients than another. The decisive factors are mainly the different thickness of the material and the way light passes through the individual layers.
Purple marks are therefore most often visible:
- in the apex area,
- above small irregularities in the base,
- in areas with a thicker Top Coat layer,
- where a thicker layer of the previous enhancement remains.
Old enhancement material can play a bigger role than it seems
Nail technicians may encounter a similar effect particularly during regular infills.
If thicker areas of old material are not fully removed during a previous refill, areas with different total thicknesses can remain beneath the new enhancement.
After applying a new base, colored gel polish and Top Coat, light then passes through more material in these areas than on the rest of the nail. In direct sunlight, these areas can appear as subtle blue-purple “shadows”, even though the surface of the enhancement looks perfectly smooth at first glance.
From our salon experience, we know that an insufficiently even base is one of the common reasons why this optical effect appears only on certain parts of the nail.
For this reason, we recommend paying close attention to base preparation during every infill:
- remove excess old material,
- create a smooth transition between the existing enhancement and the natural nail,
- check the surface against the light before applying the colored gel polish.
A carefully prepared base influences not only the appearance of the enhancement, but also its long-term color stability.
How to reduce the risk of purple marks
Although it is not possible to control the intensity of sunlight or every property of the materials used, correct application can significantly reduce the risk of this optical effect.
The foundation is a uniform nail structure.
- Create the smoothest possible base already when working with the base product or builder gel.
- Do not leave structural correction until the Top Coat stage.
- Apply colored gel polish and Top Coat in even layers.
- Use a UV/LED lamp that corresponds to the manufacturer’s recommendations.
- Follow the recommended curing times.
A common mistake is trying to cover small irregularities with a thicker Top Coat layer. In reality, this can make the optical effect even more noticeable.
The primary purpose of a Top Coat is to protect the enhancement and create long-lasting shine. Structural irregularities should therefore be corrected in the earlier application stages.
Choose the Top Coat according to the type of enhancement
Not every Top Coat is designed for the same purpose. Some products focus mainly on maximum shine, others on flexibility and others on long-term color stability. Their optical properties can also vary.
We therefore recommend choosing the Top Coat not only according to the desired finish, but also according to the type of enhancement and the shades being used.
For very dark shades, it can be beneficial to use a product that affects the final color as little as possible, such as BGE or Brilliant Gloss.
For white, French manicure or milky shades, on the other hand, Top Coats that help maintain a bright appearance over time and slow down the natural yellowing of the material may be useful, such as Perfect Shine DENATO or generally glossy finishes that show a characteristic response under UV light.
Our experience shows that the correct combination of colored gel polish and Top Coat often has a greater impact on the final appearance than changing only one product.
Are purple marks a reason for a complaint?
A client may come to the salon with a photo taken in direct sunlight and point out blue-purple marks that she noticed. Is this a reason for a complaint?
In most cases, no.
If the blue-purple tint appears only in intense sunlight and disappears within a few minutes after moving indoors, it is usually a natural optical effect rather than a manufacturing defect in the material.
The situation is different if the color change remains even without sunlight or is accompanied by other signs, for example:
- loss of shine,
- cracking of the Top Coat,
- lifting or peeling of the material,
- other visible signs of damage to the enhancement.
In such a case, it is advisable to check the entire application process, the products used and the condition of the UV/LED lamp, and if necessary contact the manufacturer.
Being able to distinguish a normal optical property from an actual material defect is important not only when assessing a complaint, but also when communicating with the client. The ability to explain this type of effect clearly and professionally is one of the signs of an experienced nail technician.
Why is this effect discussed more often than before?
Many nail professionals feel that similar optical effects have become more noticeable only in recent years.
The development of modern UV/LED materials is constantly moving forward. Manufacturers continually adjust formulations to meet current legislative requirements as well as increasing demands for safety, color stability and long-term durability.
Modern materials may therefore use new combinations of photoinitiators, UV stabilizers, pigments and other functional ingredients. Each manufacturer works with its own formulation, and these can differ slightly in their optical properties.
This does not automatically mean that modern materials are of lower quality. In many respects, they offer greater stability and better application properties than previous generations.
It is, however, important to understand that different formulations may react differently under extreme light conditions. This is why the correct combination of individual products and compliance with the recommended application system are more important than ever.
Why can some Reflective gel polishes change shade?
In addition to blue-purple marks, nail technicians also discuss the gradual lightening or greying of certain Reflective gel polishes.
At first glance, it may seem like the same issue. In reality, however, the two effects have different causes.
With purple marks, we are primarily dealing with a temporary optical effect that usually disappears once the lighting conditions change.
With some Reflective gel polishes, prolonged exposure to external influences may lead to a change in the appearance of the color pigments that create the final shade of the gel polish.
It is important to emphasize that this change does not concern the reflective particles themselves. These are generally very stable and retain their characteristic light reflection. If the shade changes, the cause is usually related to changes in the properties of the pigments or their interaction with external influences.
As with classic colored gel polishes, the final color stability therefore depends on the entire formulation of the product, not only on the reflective particles.
A change in shade may be more noticeable in:
- intense pink shades,
- neon colors,
- certain purple pigments,
- very saturated red shades.
This does not mean that a change must always occur. In most cases, a Reflective gel polish retains its original appearance throughout the wear period.
Why does the shade change for some clients but not for others?
There is no single simple answer to this question.
Two clients may wear the same gel polish shade, the same Top Coat and the same application system and still have different experiences. The decisive factor is usually not one single influence, but the combination of several factors.
The final appearance of the enhancement can be influenced by:
- the intensity of sunlight,
- the length of time spent in direct sunlight,
- regular use of tanning beds,
- the use of sunscreen products,
- contact with household chemicals,
- swimming in pools or the sea,
- mechanical stress on the hands,
- the quality of polymerization,
- the correct choice of Top Coat.
Each of these influences is common on its own. However, when several occur at the same time, the resulting effect can become more noticeable.
This is why one client may wear the same shade for years without any visible change, while another notices slight lightening or a change in shade after a summer holiday.
A summer holiday puts the nail enhancement under exceptional stress
Our long-term experience and the questions we receive from nail technicians show that many similar situations occur during summer holidays.
Within just a few days, nails can be exposed to a combination of influences that are usually far less intense during normal everyday wear.
The enhancement may be exposed simultaneously to:
- more intense UV radiation,
- higher ambient temperatures,
- sunscreen products,
- sea water,
- pool chemicals,
- frequent contact with water,
- sand and mechanical stress.
Each of these factors is a normal part of a summer holiday. Their combination, however, can place greater stress on the surface of the enhancement than normal everyday use.
What role do sunscreen products play?
Sunscreen products are an essential part of protecting the skin against UV radiation. They contain a mixture of UV filters, oily components and other substances that may leave a very thin film on the surface of the Top Coat after contact with the nails.
In most cases, this does not mean that the material has been damaged. However, this film may temporarily change the way light is reflected and therefore influence the appearance of the enhancement. With repeated and prolonged exposure combined with intense sunlight and other factors, it may also contribute to faster wear of the surface layer.
For this reason, we recommend gently removing excess sunscreen product from the nail surface after application. This simple habit can help maintain long-term shine and color stability.
Sea water and pool water do not dissolve gel polish
Some clients believe that sea water or chlorine “eat away” or dissolve gel polish or Top Coat. This statement is not accurate.
Polymer materials used in professional nail enhancement are resistant to normal contact with sea water and chlorinated water. The water itself is therefore not the direct cause of a color change or damage to the enhancement.
However, prolonged exposure in combination with intense UV radiation, high temperatures, sunscreen products and mechanical stress can contribute to faster natural aging of the surface layer.
If the Top Coat is already partially worn or contains microscopic cracks caused by normal wear, changes in appearance may become more noticeable.
After swimming, we therefore recommend rinsing the hands with clean fresh water. This is neither an obligation nor a condition for correct wear, but a simple preventive measure that helps remove residues of salt, chlorine and cosmetic products.
What did DENATO’s internal tests show?
We repeatedly receive questions about changes in the shade of gel polishes and Top Coats during training sessions and through customer support, even though these situations are not particularly frequent. For this reason, we decided to carry out our own long-term observation.
We prepared several sample tips with different gel polish shades and exposed them to intense daylight for an extended period of time. We continuously monitored any possible changes in shade and overall appearance.
During this period, we did not observe any visible color change on the tested samples.
This result does not mean that a shade change cannot occur during normal wear. Rather, it supports our long-term experience that sunlight alone is usually not the only cause of these effects.
The final appearance of the enhancement is influenced by a combination of factors – application technique, wear conditions, mechanical stress, cosmetic products and the environment in which the client spends time.
These are DENATO’s internal observations based on specific materials tested. The behavior of individual products may vary according to the manufacturer, formulation and shade used.
Practical recommendations for nail technicians
Although it is not possible to control every condition the nails will be exposed to during wear, correct application can significantly reduce the risk of optical changes.
We recommend in particular:
- Create as even a base as possible.
- Follow the recommended application procedure for all layers.
- Use a high-quality UV/LED lamp that meets the manufacturer’s requirements.
- Select a suitable Top Coat according to the shade used and the type of enhancement.
- Do not use unnecessarily thick Top Coat layers to correct structural unevenness.
- Rinse hands with clean water after swimming in the sea or pool.
- Remove excess sunscreen products from the nail surface.
- Wear protective gloves when working with cleaning products.
These are not complicated rules. However, following them consistently can often determine how the enhancement will look even after several weeks of wear.
The most common mistakes that can make the optical effect more visible
- An unevenly prepared base – differences in overall material thickness can make the optical effect more noticeable.
- An excessively thick Top Coat layer – Top Coat should not replace a correctly built structure.
- Old enhancement material that has not been sufficiently evened out – remaining thicker areas may affect the way light passes through the nail.
- Uneven layers of colored gel polish – differences in the amount of material can alter the final optical appearance.
- An unsuitable combination of products – different Top Coats may have different optical properties.
- Failure to follow the recommended curing process – always respect the manufacturer’s application guidelines and use a suitable UV/LED lamp.
FAQ: Common questions about purple marks and shade changes
Why are purple marks visible only in sunlight?
Because this is an optical effect that becomes visible mainly under intense UV radiation. Indoors or in the shade, the effect is usually much weaker or disappears completely.
Do purple marks mean that the gel polish is poor quality?
In most cases, no. The effect is usually caused by a combination of the optical properties of the material, the thickness of the individual layers and the intensity of sunlight.
Can purple marks appear with different brands?
Yes. Similar optical effects can occur with materials from different manufacturers because they are connected with the properties of the materials used and their formulations. The intensity of the effect may, however, vary from product to product.
Why does the shade change for some clients but not for others?
The final appearance of the enhancement is influenced by many factors – from application technique and wear conditions to UV exposure, cosmetic products and mechanical stress. Every client may therefore have a different experience.
Can these effects be prevented completely?
There is no 100% solution. A carefully prepared base, correct application and a suitable combination of materials can, however, significantly reduce the likelihood of these effects occurring.
Summary: when is a color change a normal optical effect?
Blue-purple marks on gel polish or Top Coat may initially look like a manufacturing defect or an application error. In most cases, however, they are a temporary optical effect related to the composition of the material, the thickness of the individual layers and the intensity of sunlight.
Similarly, changes in the shade of some Reflective gel polishes are usually not caused by one single factor. The final appearance of the enhancement is influenced by a combination of the product formulation, application technique and the conditions the nails are exposed to during wear.
A carefully prepared base, a correctly selected Top Coat and compliance with the recommended application method are the best way to minimize similar optical effects.
Our experience shows that a well-informed nail technician is able not only to create a high-quality nail enhancement, but also to explain clearly to the client why certain optical effects may occur. The ability to understand materials and correctly interpret their behavior is one of the differences between routine application and truly professional work.
The development of UV/LED materials and changes in formulations
The development of modern UV/LED materials is influenced not only by technological progress, but also by European legislation focused on the safety of cosmetic products.
In recent years, manufacturers have therefore been gradually adjusting formulations, replacing some previously used substances with new alternatives and looking for an optimal combination of photoinitiators, UV stabilizers and other functional ingredients.
Modern materials may therefore have slightly different optical properties in some respects compared with their predecessors. This is not automatically a sign of lower quality, but a natural consequence of technological and regulatory development.
Understanding how modern materials behave and why their properties gradually change alongside advances in technology and legislation is one of the important characteristics of a truly professional nail technician.
Article author
This article was prepared by Lucie Králová and the DENATO expert team based on experience from professional salon practice.
Updated
This article has been updated in line with current knowledge and professional practices in the field of nail enhancement.