It might not be immediately obvious how colour can be a category for images collected to explore a theological or spiritual perspective, but let's take a closer look.
In sports broadcasting, there is a person called a colour commentator. This person's job is to add depth and interest to the mere technical play-by-play reporting of the sport's caster. This added 'colour' is what makes the programming more interesting to the average viewer than simply listening to the list of statistics and cause-and-effect events. It is colour that provides so much of the deeper information - how it feels to play the game, what the players might be thinking or going through, why this or that strategy of play is a good or bad thing.
In photography, colour also adds much to the image, especially to the feeling and message. This is just as true for monochrome (Black and White) images as it is for images intentionally colourful. First, the choice as to whether or not to explore the image in colour, or black and white, is itself an essential colour decision. Colour's absence can communicate a kind strength in high-contrast and low-key black and white. Absenting colour can also emphasise form, shape, line or texture in an image. This can create a more intellectual appeal, and a feeling of austerity.
But it is in colour photography (obviously) that colour really takes centre stage, and takes its part fully in the play and inter-play of characters in an image. In this ensemble cast, colour is often the emotional character. It can be cold or warm, it can be ominous or cheering, sentimental or sceptical. While colours (or their absence) alone can never communicate the whole of a photographer's vision, it nevertheless is essential for creating much of the depth, interest, and feel that the photographer is trying to communicate.
Many might suggest that in the pursuit of God, it is the experience of the Holy Spirit that brings colour to our spiritual lives. It is in the encounter of the Spirit, that many people find much of the joy and passion of their faith. The Spirit dwells within us, by virtue of baptism, and guides and teaches us, often through feelings, hunches, needs and desires, directed through prayer and meditation. In this encounter with the third person of the Trinity it is the faithful person often operates at a level beyond intellect alone, but more than mere feeling, and we are guided by a sense or a knowledge that appears to come from outside ourselves. This 'colour' in our faith, like that of the colour commentary, adds depth and meaning to life, and the situations, events and relationships that make our lives up. It also, as in a photograph, adds that essential level of information that communicates the feel and intent faith brings to bear on our life.
Colour in photography, like the Spirit, in faith, transcends the simple patterns shapes and textures of what we see and experience. Both add depth, communicate meaning, reveal intent and purpose, and share a feeling for what is before us in a way that goes beyond what is possible without it. It is not always easy to analyze or understand what colour is doing psychologically, nor is it always easy to understand what the Holy Spirit is doing for us spiritually, but we know when they are active, and at work, and we know that when we step back, and open our eyes to see, it is in the colours before us that true understanding will come through.