Halo lit (or reverse) channel letters can produce a dynamic signage presence when properly designed and installed. However, the color, brightness and halo depth can have a substantial impact on the effectiveness of this type of letter sign. This article examines some of the elements and characteristics for effective reverse lit channel letter halos.
光晕照明（或背光式）槽形字经过适当地设计和安装之后，可以呈现出动态的显现方式。同时，颜色、亮度和光晕深度对这种类型的标识呈现效果都有很大的影响。这篇文章研究了几种高效的背光式槽型发光字光晕的属性和特征。

Halo Color
光晕颜色

Many clients are not aware that reverse channel letter halos are available in multiple colors. (Some assume white is the only option.) Choosing the correct halo color configuration can be an important effectiveness determinant. This multiple color capability may also permit a client to match a customers branding color scheme.
许多客户还没有意识到，背光式槽型发光字光晕可以使用多种颜色。（一些人以为白色是唯一的选择。）选择合适的光晕颜色对标识呈现出的效果有很大的影响。这种多重色彩显现方式或许还能满足客户对品牌颜色设计的要求。

Consider the halo color on Photo 1 below.
以下面的图1为例，观察一下光晕的颜色。

The warmth of this orange halo is an appropriate complement to the product offering. The color orange is often associated with physical comfort and food.
橘色光晕呈现出的温暖感正好符合此标识想要表达的立意。橘色通常都是与身体舒适度和食物相关联的。

Mixing the signs halo colors is another design item to consider. Your client may also not be aware that not all letters must have the same halo color. Multiple halo colors can provide the sign with an additional attention generating element.
采用混合光晕颜色是另外一个设计理念。客户可能意识不到，不是所有的发光字都只能使用同一种颜色的光晕。多重光晕颜色可以为标识增添额外的吸引力。

For example, Photo 2 features multiple halo colors and has both strong legibility and visual impact.
例如，图2中标识的特点就是多重颜色的光晕，显示出较强的易读性和视觉冲击。

Photo 3 also mixes halo colors and has a warm and professional appearance. Red is one of the Residence Inn branding colors.
图3中的标识也混合了光晕颜色，呈现出一种既温暖又不失专业化的外观。其中红色是Residence Inn品牌颜色之一。

Photo 4 is another example of a halo color mix. This illumination design emphasizes the business name but then follows with the business type in a smaller font and different halo color.
图4是另外一个混合光晕颜色的案例。这个照明设计重点在于企业名称，后面紧接着是企业类型，它用的是较小的不同颜色的光晕。

Multiple halo colors may be an excellent method for your client to add more attention generating capacity to their reverse lit letter sign.
多重光晕颜色对客户来说或许会是最佳选择，这样他们的背光式发光字标识就会吸引更多的目光。

However, that is not always the case. A single halo color (white is the most common) may also be a perfectly appropriate configuration. Consider Photo 5.
然而，多重光晕颜色并不是所有的标识都适用。单一光晕颜色（白色是最普遍的）或许也是一种绝佳的外观选择。观察一下图5.

This sign has an excellent outline against the well proportioned white halo. The single color seems appropriate for the business type as white is often associated with cleanliness and purity. Importantly, the building also has a white façade which adds to the halo luminance.
这个标识有一个比例适当的白色光晕轮廓。单一颜色很适合该企业类型，因为白色通常是和纯洁相关联的。更重要的是，店面的正面是白色的，它和白色光晕更加匹配。

Halo Brightness
光晕亮度

Adequate halo brightness is a critical factor in the effectiveness of a reverse channel letter set. Some letter sets lack sufficient light intensity to generate an optimal halo lit effect.
适当的光晕亮度也是背光式槽形发光字呈现效果的决定性因素。一些发光字的亮度不够，所以很难呈现出最佳光晕效果。

Part of the site survey must include the environment in which the sign will function. Letters which are mounted indoors have a stronger halo brightness requirement. For example, in Photo 6, this indoor mounted reverse letter set has some width distribution but lacks adequate brightness:
一些场所必须考虑标识呈现效果所需要的环境。室内发光字需要更强的光晕亮度。例如，在图6中，该室内背光式发光字有一定宽度但是亮度不够：

This halo is not sufficiently conspicuous to create an “illumination bed” that fully outlines the sign letters. This effect may be the result of an inadequate number of LED modules, modules which have dimmed over time or failure to use a reflective paint on the letter interiors.
此光晕呈现出的照明效果不是特别明显，不能完全显示出标识字母的轮廓。这可能是由于LED模组不够造成的，模组会随着时间推移变暗或在发光字底部无法反射颜色。

Conversely, note the impact difference between that sign and this well illuminated set (also mounted indoors) in Photo 7.
相反地，我们来看一下这个标识和图7 中良好照明标识（同样是室内标识）的区别。

The letter interior configuration can be a partial determinant of halo brightness. Channel letter cans are typically constructed of aluminum, and reverse letters have both aluminum returns and faces (as opposed to the acrylic faces used on front lit letters.)
发光字内部结构是光晕亮度的决定性因素。槽形发光字字壳是用铝做成的，并且背光式发光字正面和背面都是用铝做成的（亚克力用于正面发光字。）

The default mill finish of an aluminum letter interior does not effectively reflect LED illumination. Reflective white paint is available to distribute and amplify the illumination reflection from the inside of the letter can. Painting the letter interiors for added illumination “bounce back” is a strong step toward a bright and well distributed halo.
表面经过打磨的铝字，其内部反射LED照明的效果不是特别明显。反光白漆可均匀地散布并增大发光字字壳内部的照明反射范围。为了有额外的照明“反射”效果，在发光字内部喷漆是实现明亮均匀散布光晕的重要步骤。

Last, one further step down from inadequate brightness is a halo which is conspicuously dim. Assuming these dim letters are LED (not neon) illuminated, this problem may be caused either by an inadequate LED module population or by LED which has dimmed over time and needs replacement.
最后，造成标识亮度不够的另一个原因是光晕明显变暗。假设这些暗淡的发光字都是用LED（不是霓虹灯）照明，那么导致标识暗淡的原因要么是LED模组数量不够，要么是LED已经随时间推移变暗，需要更换新的LED来照明了。

A dim halo can be worse than no halo at all. It is essentially an advertisement for a sign that was either poorly constructed or has been not been properly maintained. Either way, it is not positive advertising.
暗淡的光晕比没有光晕更糟糕。标识实质上就是广告宣传，如果光晕比较暗淡，原因要么是制作的很差，要么是没有进行适当地维护。无论哪一种原因，它都不是一个积极的广告宣传。

Halo Width
光晕宽度

Halos also vary in terms of width (i.e., the distance behind the letter that the halo “fans out.”) Ideally, the halo will form an “illumination bed” against which the letters will be outlined. A halo which combines both brightness and appropriate width can create a dramatic illumination effect.
光晕宽度（即光晕在发光字后面散开的距离）也分为很多种。理想情况下，光晕会在发光字轮廓下形成照明带。亮度和宽度均适当的光晕能够给人留下深刻的印象。

On the other hand, an overly thin halo may defeat the reverse lighting purpose. If the halo does not disperse an adequate distance behind the letters, the illumination impact can be diminished. (See Photo 8)
同时，太过纤细的光晕可能会使背光式照明效果大打折扣。如果光晕在发光字后面散开的距离不够时，照明效果就会减弱。（见图8）

One of the causes of halo width is the letter mounting distance from the wall.The appropriate mounting distance is typically 1.5” to 2”. Letters which do not have sufficient façade mounting distance may result in a thin halo.
发光字与墙面之间的安装距离是影响光晕宽度的因素之一。最佳安装距离通常是在1.5”到2”之间。如果安装距离不够就会造成光晕太过纤细的后果。

Facade Color Effect
发光字正面颜色

A careful examination must also be made between the customers desired halo color and the current color of the building façade. Halo illumination may appear in a different hue than intended if it is reflected off a colored building surface.
要仔细观察客户要求的标识光晕颜色和现有建筑物表面颜色之间的匹配度。如果反射正面为彩色的建筑物，光晕照明可能会呈现出和预期不一样的色调。

For example, if a building has a red façade and the installed sign has a white halo, some of the red surface color may carry over into the halo appearance. The customer should be made aware of that potential issue prior to installation.
例如，如果建筑物的正面是红色的，而标识的光晕是白色的，那么部分红色就会融进白色光晕中。客户在安装之前首先要考虑到潜在的问题。

If your review of the site shows there may be a potential surface color carry-over problem, one potential solution is to mount a backer panel behind the sign. The correct usage of such a panel can change a problematic illumination surface to an ideal halo lighting environment, as seen in Photo 9.
如果你觉得这个位置可能会出现正面颜色融合的问题，那么解决方案就是在标识后面安装一个支撑面板。正确使用这种面板可以解决颜色融合问题，从而变成理想中的光晕照明效果，如同图9中的标识。

However, reverse letters mounted to backer panels may also have issues. For example, if the panel has a shiny surface (like a “mirror finish”) it may show a night reflection of the LED modules.
然而，安装在支撑面板上的背光式发光字同样也存在一些问题。例如，如果这个面板的表面有光泽（如同“镜面”），可能会出现LED模组的夜间反射现象。

The key question for your customer is their color preference on the overall halo appearance. If you see a potential issue at the sign location (i.e., the surface color may dilute the halo color) let them know the importance of a backer panel.
客户在意的是整个光晕呈现出的色调。如果你觉得会出现发光字表面颜色削弱光晕颜色的现象，那么就告知客户支撑面板的重要性。

Conclusion
结论
Halo lit channel letters can have a dramatic signage impact when constructed correctly, but vary in terms of halo and mounting quality. The halo color, brightness and width can each have an impact on the overall presentation of the reverse lit sign. Further, the mounting surface and color will also influence the halo appearance. A careful site survey will help to uncover potential issues with the reverse lit letter set appearance.
制作良好的光晕照明槽形发光字会有出人意料的效果，同时光晕和安装质量都略有不同。光晕颜色、亮度和宽度都会对整个背光式照明标识有一定影响。更进一步讲，安装面板和它的颜色也会影响光晕的呈现效果。细致的研究调查会让你发现背光式发光字外观存在的潜在问题。
*文章来源于亚洲标识