Cyanotype

Cyanotype technique using light sensitivity of iron salts. As the creator of cyanotype considered Willam John Frederick Herschel (1792-1871). Herschel is best known for the discovery in 1819 in the capacity of sodium thiosulfate to dissolve the silver chloride. This discovery (1839 year), in conjunction with kalotypią William Henry Fox Talbot (1800-1877), the possibility of capturing images. That same year, Herschel also formulated the terms used today ie: photography, negative and positive. In their experiments searching for cheaper methods of reproduction - unfortunately no photos, but notes. The method, invented by Herschel - Richard T. Rosenthal called cyjanotypią.Anna Atkins (1799-1871), botanist, one of the first female photographers, in 1841 she met Talbot (creator kalotypii) friend of her father. Under the influence of an interest in photography Talbot. For his work as an elected Cyanotype affordable, easy and inexpensive to produce. Released in 1843, the first volume of books Fri British algae: Cyanotype Impressions. " This was done in the whole book Cyanotype (including text and illustrations). Ahead of this book Talbot Fri "The Pencil of Nature" (1844). His works were performed piling leaves and flowers directly on paper. Issued a total of 12 parts, 424 photos illustrating them in the cyanotype technique. Rediscovered in 1966 when it appeared on the auction of its książka.Francuz Henri Jean-Louis le Secq (1818 -1882), he used this method in the early 50s of the XIX century. In 1852 he received from the Commission des Monuments Historiqes commissioned the preparation of documentation in the cathedrals of Rheims and Chartres. Partially done work in cyanotype. This method also used the Hyppolite Bayard (1801-1887), Dr. Peter Henry Emerson (1856-1936) and of course the same Talbot. Since 1880, cyanotype paper was produced in large quantities. Used it often - even in the 90s of the twentieth century - the architects and engineers to make copies of technical drawings. Inexpensive method of exposing the contact exposure on paper soaked in salt solution of potassium ferrocyanide and iron oxide. Under the influence of light reaction of salt iron oxide which darkens giving the Prussian blue. Areas covered are white. Prints are called Blueprint (blue print). The resulting images are often contrasting and probably not suitable for halftone photographs. Finished prints are apparently not very stable, but until today pictures from 1843.

White Balance

The correct white balance (WB) setting gives us above all a faithful reproduction of colors with no color casts. which is pure white, neutral gray. At the same time the white balance can be used to take images in a particular climate. For example, in the room where the lights are just an ordinary light bulbs with tungsten white balance setting for just such a light source to get the correct colors. But when you set the white balance to daylight this picture comes out very yellow in tone. Adjusting settings we can change the balance of the dominant color saturation.

More about color temperature

The concept of color temperature is applied for color photography. As previously mentioned, our eye has the ability to adapt to lighting conditions, almost always perceive colors correctly, even when the lighting will have a strong dominant such as red as the sunset. However, in such situations, digital equipment requires proper setting. For measuring the color temperature gauges are special. They can show the actual color temperature and the number of the filter, which compensates us dominant. The digital video recording can match the final color image to the currently prevailing lighting conditions. Serves the function of white balance (WB). Its use is to match the values adjustable to the prevailing light conditions.

Color Temperature

Very helpful concept is the color temperature of light. Explaining the issue, Let's take an example. As everyone knows, we need to get a light warm up a body to a very high temperature. On this principle operate incandescent bulbs (the sun, too). Tungsten filament is heated by flowing through an electric current is not and starts to shine. Depending on this, the high temperature as it warms, it will shine a very bright or less intense, and thus, the color of light will change. Very easy to see the effect of torches, when the batteries are exhausted and the bulb gradually begin to produce less and less light - its color changes from dark yellow to yellowish red through and then goes off. It is associated with a drop in temperature to which the tungsten wire is heated up. The lower the temperature, the light is less intense and committed to its color red, the higher the temperature, the more light and its color changes in the direction of white. In case of further raising the temperature starts to dominate the color blue. As you can see, a given temperature corresponds to the specific color of light.

Few things about the light

White light is really a mixture of waves of different lengths and what's involved, different colors ranging from blue through green, ending in the red. The scope of the visible spectrum below shows the graphic illustration. Radiation at wavelengths shorter than violet is called ultra-violet, while the waves longer than red are called infrared radiation. The human eye registers the specified portion of spectrum known as visible waves. Photographic and digital sensors are so designed as to record the same spectral range, which captures our eye. White light is a mixture of all colors, but when one of them begins to dominate the resultant color of light changes. Our eye is able to automatically adapt to a fairly broad range of such changes, and usually we see the color properly, while the digital sensor that possibility in itself does not, and record exactly what is in reality.