Sixth entry- Visual Resources and Technology

Hai everyone and we meet again in my entry for today! Basically, we are going to uncover the process of producing and transforming an analogue into digital images. We also going to further explains on scanning, digital imaging and 2D vs 3D images as well so are you ready guys?Here we go!!

Firstly, allow me to define what is analogue and how does analogue associates with digital photography.  Analog photography is photography that uses a progressively changing recording medium, which may be either chemical process-based (e.g., photographic film or plate) or electronic (e.g., vidicon or CCD sensor). Analog photography has come to mean anything that is "not digital" despite some of controversy over the question of whether the use of film is a true analog process.

In a film camera that uses the gelatin-silver process, light falling upon photographic emulsions containing silver halides is recorded as a latent image. The latent image is subjected to photographic processing, which makes it visible and insensitive to light. In a video camera or digital still camera, the signal is captured with a video camera tube or charge coupled device sensor, which sends the picture to be processed by the camera's electronics. The signal can be transmitted or recorded on a storage device for later playback.

All film and paper is treated in a series of chemical baths, which are closely monitored and maintained at a specific temperature and treatment time. Developer baths are most sensitive to deviations from the standard time and temperature of treatment; other baths are less sensitive.

Black and white negative processing

Black and white negative processing is the chemical means by which photographic film and paper is treated after photographic exposure to produce a negative or positive image. Photographic processing transforms the latent image into a visible image, makes this permanent and renders it insensitive to light.

1. The film may be soaked in water to swell the gelatin layer, facilitating the action of the subsequent chemical treatments.
2. The developer converts the latent image to macroscopic particles of metallic silver.
3. A stop bath, typically a dilute solution of acetic acid or citric acid, halts the action of the developer. A rinse with clean water may be substituted.
4. The fixer makes the image permanent and light-resistant by dissolving remaining silver halide. A common fixer is hypo, specifically ammonium thiosulfate.
5. Washing in clean water removes any remaining fixer. Residual fixer can corrode the silver image, leading to discolouration, staining and fading.

The washing time can be reduced and the fixer more completely removed if a hypo clearing agent is used after the fixer.

The washing time can be reduced and the fixer more completely removed if a hypo clearing agent is used after the fixer.

1. Film may be rinsed in a dilute solution of a non-ionic wetting agent to assist uniform drying, which eliminates drying marks caused by hard water. (In very hard water areas, a pre-rinse in distilled water may be required - otherwise the final rinse wetting agent can cause residual ionic calcium on the film to drop out of solution, causing spotting on the negative.)
2. Film is then dried in a dust-free environment, cut and placed into protective sleeves.

Once the film is processed, it is then referred to as a negative.

The negative may now be printed; the negative is placed in an enlarger and projected onto a sheet of photographic paper. Many different techniques can be used during the enlargement process. Two examples of enlargement techniques are dodging and burning. Alternatively (or as well), the negative may be scanned for digital printing or web viewing after adjustment, retouching, and/or manipulation.

In modern automatic processing machines, the stop bath is replaced by mechanical squeegee or pinching rollers. These treatments remove much of the carried-over alkaline developer, and the acid, when used, neutralizes the alkalinity to reduce the contamination of the fixing bath with the developer.

Black and white reversal processing

This process has three additional stages:

1. Following the stop bath, the film is bleached to remove the developed negative image. The film then contains a latent positive image formed from unexposed and undeveloped silver halide salts.
2. The film is fogged, either chemically or by exposure to light.
3. The remaining silver halide salts are developed in the second developer, converting them into a positive image.
4. Finally, the film is fixed, washed, dried and cut.

Colour processing

Chromogenic materials use dye couplers to form colour images. Modern colour negative film is developed with the C-41 process and colour negative print materials with the RA-4 process. These processes are very similar, with differences in the first chemical developer. The C-41 and RA-4 processes consist of the following steps:

1. The colour developer develops the silver negative image, and byproducts activate the dye couplers to form the colour dyes in each emulsion layer.
2. A rehalogenising bleach converts the developed silver image into silver halides.
3. A fixer removes the silver salts.
4. The film is washed, stabilised, dried and cut.

In the RA-4 process, the bleach and fix are combined. This is optional, and reduces the number of processing steps. Transparency films, except Kodachrome, are developed using the E-6 process, which has the following stages:

1. A black and white developer develops the silver in each image layer.
2. Development is stopped with a rinse or a stop bath.
3. The film is fogged in the reversal step.
4. The fogged silver halides are developed and exhausted developing agents couple with the dye couplers in each layer.
5. The film is bleached, fixed, stabilised and dried as described above.

In some old processes, the film emulsion was hardened during the process, typically before the bleach. Such a hardening bath often used aldehydes, such as formaldehyde andglutaraldehyde. In modern processing, these hardening steps are unnecessary because the film emulsion is sufficiently hardened to withstand the processing chemicals.

Oh man! There’s a lot of info we have here! I guess we should be lucky and thanks the scientists mostly as they making our life easier and simple. I never knew that processing a photo would that complicated and time-consuming. Oh well, I hope you guys still have vacant rooms for our next subtopics which are scanning, digital imaging and 2D vs 3D images.

Scanning in photography is no stranger to it and depending for each other. This website will guide us on how to scan photographs properly. In this website, scanning needs careful approach and user needed to use a proper software to scan their photographs. Windows Fax and Scan is recommended for a beginner user it need to be install with the printer. 

In digital imaging, A digital photograph may be created directly from a physical scene by a camera or similar device. Alternatively, a digital image may be obtained from another image in an analogmedium, such as photographs, photographic film, or printed paper, by an image scanner or similar device. Many technical images—such as those acquired with tomographic equipment, side-scan sonar, or radio telescopes—are actually obtained by complex processing of non-image data. Weather radar maps as seen on television news are a commonplace example. The digitalization of analog real-world data is known as digitizing, and involves sampling (discretization) and quantization.

Finally, a digital image can also be computed from a geometric model or mathematical formula. In this case the name image synthesis is more appropriate, and it is more often known as rendering.

Digital image authentication is an issue for the providers and producers of digital images such as health care organizations, law enforcement agencies and insurance companies. There are methods emerging in forensic photography to analyze a digital image and determine if it has been altered. Previously digital imaging depended on chemical and mechanical processes, now all these processes have converted to electronic. A few things need to take place for digital imaging to occur, the light energy converts to electrical energy- think of a grid with millions of little solar cells. Each condition generates a specific electrical charge. Charges for each of these "solar cells" are transported and communicated to the firmware to be interpreted. The firmware is what understands and translates the color and other light qualities. Pixels are what is noticed next, with varying intensities they create and cause different colors, creating a picture or image. Finally the firmware records the information for future and further reproduction.

There are several benefits of digital imaging. First, the process enables easy access of photographs and word documents. Google is at the forefront of this ‘revolution,’ with its mission to digitize the world’s books. Such digitization will make the books searchable, thus making participating libraries, such as Stanford University and the University of California Berkley, accessible worldwide. Digital imaging also benefits the medical world because it “allows the electronic transmission of images to third-party providers, referring dentists, consultants, and insurance carriers via a modem”. The process “is also environmentally friendly since it does not require chemical processing”. Digital imaging is also frequently used to help document and record historical, scientific and personal life events. 

Last but least, we are going to do comparison of 2D and 3D images. What are the differences between the two images? Isn’t it the same? Certainly not! In this website, the author compared both images in terms of their resolutions and pixels. Apart from that, advantages and disadvantages also been dicussed and it greatly shows that 3D images provides better resolution than 2D images. 

So that’s it guys! Enough for today okay! Too many input can cause memory loss to your brain which can lead to depression! Just kidding. Don’t take it too serious la. As long as you gus understand the concept, the process of learning will develop and your brain automatically will keep the information in your either short-term or long term memory. I’l recap what we have learned today. We learned on the process of making analogue for digital images and also their advantages respectively. We also learned on scanning photographs, discussed digital imaging and conducting comparison in between 2D VS 3D images. So, for next entry, we will study and use more on Adobe Photoshop and manipulate images by using te editing software. Lastly, strive hard, earn hard! Fighting!