Comparison Vita WH-0021 vs Forte MC-9100

The degree of light penetration provided by the mask filter, in other words, the degree of darkening (light attenuation) provided by the product.

The degree of dimming is indicated in DIN units, the larger its value, the lower the light transmission (that is, the darker the filter). Note that for chameleon masks (see "Type"), this paragraph indicates the characteristics of the light filter in the off state — that is, when it is not darkened and as transparent as possible. So for such products, the degree of light penetration is more of a reference value, and it is necessary to evaluate the actual degree of protection in "chameleons" by the minimum and maximum degree of dimming (see below).

In turn, for masks and glasses with permanent filters, the degree of light penetration is the main performance characteristic. Here you need to proceed from the following: a darker filter, on the one hand, provides higher protection against bright light, on the other hand, worsens visibility. So the optimal values for most welding work are 10 – 12 DIN, it is in this range that the characteristics of most modern masks / goggles without the "chameleon" function lie. More detailed recommendations on the optimal transparency of light filters for different situations can be found in special sources.

The smallest degree of obscuration provided by the chameleon mask (see "Type") when the light filter is activated. Recall that dimming is indicated in DIN units, the larger the number in this paragraph, the darker the filter.

This parameter is indicated only for models with dimming control (see "Functions"). From the minimum degree of dimming depends on the extent to which you can adjust the light transmission. At the same time, we recall that a darker light filter protects better from bright light, but worsens visibility; so for some tasks, a relatively low level of obscuration may be optimal. Accordingly, the lower this indicator, the wider the adjustment range of the filter, the more opportunities the user has to adjust it (with the same maximum threshold). On the other hand, the expansion of the adjustment range significantly affects the cost, and such characteristics are not always required. Therefore, nowadays, you can find chameleon masks both with a small ( 5 DIN and even less), and with a fairly significant minimum dimming ( 7 DIN or even 9 DIN). And it’s worth choosing here, depending on what is more important for you: an extensive range of adjustment or low cost.

The turn-on time of the filter in the chameleon mask (see "Type"), in other words, the time between striking the arc and darkening the filter to the operating level.

From a safety point of view, the turn-on time should be as short as possible: the faster the "chameleon" works, the less bright light from the arc enters the welder's eyes. On the other hand, reducing the reaction time affects the cost of the product. So for relatively small volumes of work, it is quite acceptable to use relatively “slow” masks — for 100 μs or more(especially since even in the simplest models, the reaction time does not exceed 1200 μs, while theoretically the maximum allowable value is 2000 μs). But for more serious use, you should pay attention to more "fast" options; nowadays, you can find masks with response times from 75 to 100 µs, from 50 to 75 µs, and even less than 50 µs.

Class is a complex indicator that determines the overall quality of the light filter in a chameleon mask (see "Type"). The class is indicated by 4 numbers, each of which describes a specific optical parameter. So, the first number indicates the overall clarity and lack of distortion; the second is the degree of light scattering; third — uniformity of blackout (presence/absence of visible blackout spots); the fourth is the angular dependence (how much the filter brightens when the angle of view deviates from the perpendicular). In each case, the larger the number, the worse this parameter is. The perfect indicator is considered to be 1/1/1/1, but in fact it is very difficult to achieve an perfect angular dependence, and there is no need to. Therefore, an indicator of 1/1/1/2 is considered quite sufficient even for a high-end professional filter.

The size of the transparent part of the light filter — the "working window", the area through which the welder sees the place of work. A larger working window provides ease of use and a wide field of view, but it significantly affects the cost of the mask and somewhat reduces the strength of the light filter.

The overall dimensions of the light filter for which the mask is designed, taking into account the working window, protrusions for mounting, batteries, sensors and other structural elements. This indicator is especially important for models that are not equipped with light filters: without knowing the size, it is very difficult to choose the right cartridge. In other cases, data on the size of the cartridge is needed mainly when looking for a replacement for a failed colour filter.

The ability to manually select the degree of darkening of the filter in the chameleon mask. This feature is found mainly in professional models; it allows the welder to manually adjust the light transmission for specific conditions. The need to adjust the dimming is due to the fact that for some types of work (for example, TIG welding of ferrous metals), the brightness of the arc is relatively low, and in order to see the weld pool normally, dimming of only 8-9 DIN is enough instead of the usual 12 DIN or more .

The ability to change the sensitivity of the sensors responsible for the operation of the light filter in the "chameleon". Thanks to this function, you can adjust the filter in such a way that it is guaranteed to turn on from the arc and at the same time does not react to extraneous light sources. sensitivity adjustment is especially useful when there is numerous extraneous "flare" (for example, when several welders work close to each other, in bright sunlight, etc.).

The ability to manually set the delay time between the disappearance of the arc and turning off the filter in the chameleon mask. Such a delay is highly desirable in the light of the fact that even after the arc is turned off, the heated metal continues to glow for some time; therefore, it is advisable not to turn off the filter immediately. Adjusting the delay time allows the welder to independently choose the time to return to the non-working (maximally transparent) state.