Một bài viết rất hay từ retouchingacademy.com về retouching ảnh sản phẩm, ở đây bàn về cách chỉnh sửa các vùng sáng tối và bóng đổ. Kiên trì quay tay, điều hay sẽ tới…..:v :)) Keep moving 😉
Everything you do in any field of photography and retouching starts with an idea, but to achieve your vision, you must know how to shape, control, and modify the light that illuminates your subject. As a product photographer and retoucher, understanding the fundamentals of light and how it interacts with different surfaces is critical to my work.
Hard Light & Soft Light
You may already know the basics of such qualities of light as its hardness and diffusion, but to become an expert in product photography and retouching you must not only understand these basics, you must also know why and when to use each type of light (hard and soft) to their best advantage. Soft light is a good solution in many situations: portraits, fashion, beauty, architecture, and products. It is typically a flattering and diffused light that can illuminate your subject evenly without creating harsh shadows. However, the same light source can also create harsh illumination depending on its distance from the subject and the size of the light modifier mounted on it. The closer the light source is to the subject, the softer the light becomes. The larger the light source in relation to the subject, the softer it becomes, and vice-versa. Check these Fstoppers articles by Julia Kuzmenko McKim, in which she talks about the light qualities for Beauty, Fashion & Portrait photography: How To “Read” Light In Photography – Part 1 and Part 2. Hard light is a good solution for many occasions, but some may consider it more difficult to master because it creates harsh shadows with more noticeable edges, exaggerates the texture of the surface of the subject and is visible clearly in reflective surfaces. Even if you are less comfortable using hard light in general, you should understand how to use it to create more contrast or to highlight a particular part of an image. In the end, illuminating products is the same as it is in beauty and fashion: with light you show something and with shadows you hide something. Products are commonly illuminated using both types of light, so you should know the benefits and limitations of each to use them well together.
Reflectors & Reflections
A while ago, I happened to be retouching an image of a white porcelain product for my client who, when asked, provided this simple brief: “Fix the reflections perfectly”. Product photographers love well-illuminated highlights and reflections. They also require that the retoucher maintain and even improve those highlights and reflections in post-processing, and that is where your general knowledge of the product’s structure kicks in. Luckily for me, the photographer knew his subject well enough to create pleasing reflections that only needed minimal polishing. However, I also had to draw or elongate the reflections in that particular image, so to give them a natural look, I had to know the shape of the subject and how its surface interacted with the light. My photography teacher taught me a really simple rule to follow: KISS (Keep It Simple Stupid). To illuminate commercial product shots, the only things you might need is sunlight and a few reflectors. Creating too complex a lighting setup can ruin your product shot by introducing distracting shadows, unwanted highlights, or regions of overexposure. Thus, start with one light source and only add more if you cannot create the desired result with the one light and some reflectors. Also remember that reflectors can be used to block the light (a flag). Reflections are not always wanted in an image, depending on the product, but are important when shooting objects with reflective surfaces, though even then I recommend keeping them subtle. As a retoucher, you may be asked to remove distracting reflections in post that were unavoidable during the shoot, such as those caused by the lighting that was necessary to illuminate the subject.
The Variation of Products
One of the key things to keep in mind when photographing and retouching products is their diversity. Products come in a variety of sizes and shapes, with surfaces composed of different materials that are quite different than those found in fashion or beauty work. Product designers frequently combine different materials to create a new and exciting product that will stand out from the crowd. You will need to know how these materials work together and separately. Non-reflective materials are usually easier to fix than highly reflective ones such as glass and diamonds. Even though such objects are transparent and highly reflective, they still have shape and it is your job to ensure your client’s customers can see that. How? By controlling the light and shadows to bring more dimensionality to the product. Specialize in one field of products (or material) at the beginning, then expand from there.
Retouching Product Images
Sometimes, you must do the main work in post because the photographer cannot get everything exactly right in-camera. For example, you might need to combine different frames to produce the final image, but you must understand how these separate frames work together to achieve a proper result. Always remember when retouching products the importance of accurate color, shape, and texture. Keep the texture rich and truthful without blurring it and do not make additional corrections that drastically change the original product. With time, you will learn to use the right tools to fix patterns, remove dust or scratches from glass, draw reflections, or even recolor a blue t-shirt to black. The tools for better product retouching are basically the same ones used in fashion and beauty. There is no real magic behind it, just different skill levels. Every detail matters. Of course, there are myriads of different products in the world and almost everyday you can spot a new kind of texture or shape, so how will you know what lighting will work best? Well, to be honest, you won’t always know, but by honing your skills, you will have a much better chance at getting it right with an educated guess. The key to better product photography and retouching lies in knowing the basics (studio lighting, software, light behavior, etc) and how to apply them to advanced scenarios.
Credit: Academy Retouching
Original link: Here.