Alamar ruwa

## '''Alamar ruwa'''
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Alamar ruwa ita ce hoto mai ganowa ko tsari a cikin takarda wanda ke bayyana a matsayin inuwar haske/duhu daban-daban lokacin da hasken da aka watsa ya duba shi (ko lokacin da haske mai haske ya duba shi, a saman bangon duhu), wanda ya haifar da kauri ko bambance-bambance a cikin takarda. An yi amfani da tambarin ruwa akan tambarin aikawasiku, kuɗaɗe, da sauran takaddun gwamnati don hana jabu. Akwai manyan hanyoyi guda biyu na samar da alamar ruwa a cikin takarda; da Dandy yi tsarin, da kuma mafi hadaddun Silinda mold tsari.
Alamomin ruwa sun bambanta sosai a cikin iyawarsu; yayin da wasu a bayyane suke akan dubawa na yau da kullun, wasu kuma suna buƙatar wasu nazarin don zaɓar. An samar da kayan taimako iri-iri, kamar ruwan alamar ruwa wanda ke jika takarda ba tare da lalata ta ba. Alamar ruwa tana da amfani sosai wajen tantance takarda saboda ana iya amfani da ita don yin ƙawancen soyayya da zane-zane, gano girma, alamun kasuwanci da wurare, da tantance ingancin takardar. Hakanan ana amfani da kalmar don ayyukan dijital waɗanda ke raba kamanceceniya da alamun ruwa na zahiri. A wani yanayi, za a iya amfani da bugu a kan abin da aka buga a kwamfuta don gano fitarwa daga sigar gwaji mara lasisi na shirin. A wani misali, ana iya sanya lambobin gano lambobin azaman alamar ruwa na dijital don kiɗa, bidiyo, hoto, ko wani fayil. Ko mai zane yana ƙara alamar sa hannu na dijital, hoto, tambari a cikin zane-zanen dijital su azaman mai ganowa ko ma'aunin hana karya.
## '''Tarihi'''
An fara gabatar da alamun ruwa a Fabriano, Italiya, a shekarar alif 1282.A lokacin, an ƙirƙiri alamomin ruwa ta hanyar canza kauri na takarda yayin wani mataki na aikin masana'anta lokacin da yake da rigar.
 
## '''Tsari'''
Tsarin nadi na Dandy
Ra'ayin hangen nesa na dandy roll daidai da ƙirƙira na'urar yin takarda ta al'ada wacce ke haɗa alamomin ruwa a cikin takardar.
A al'adance, an yi alamar ruwa ta hanyar burge tambarin ƙarfe mai rufin ruwa a kan takarda yayin masana'anta. Ƙirƙirar daddy roll a 1826 da John Marshall ya yi ya kawo sauyi ga tsarin alamar ruwa kuma ya sauƙaƙa wa masu samarwa su sanya alamar takarda.
Dandy roll ɗin nadi ne mai haske wanda aka lulluɓe shi da wani abu mai kama da allon taga wanda aka lulluɓe da tsari. Ana yin layukan suma ta hanyar wayoyi da aka shimfiɗa waɗanda ke tafiya daidai da kusurwar dandali, kuma ana yin layukan daɗaɗɗen layukan ta hanyar wayoyi masu sarƙoƙi waɗanda ke kewaya kewaye don tabbatar da wayoyi da aka shimfiɗa zuwa nadi daga waje. Saboda wayoyi masu sarkar suna a waje da wayoyi da aka dage, suna da tasiri mafi girma akan ra'ayi a cikin ɓangaren litattafan almara, don haka bayyanar su mafi ƙarfin hali fiye da layin da aka shimfiɗa.
Ana mayar da wannan embossing zuwa ɓangarorin ɓangaren litattafan almara, tare da matsawa da rage kauri a wannan yanki. Saboda sashin da aka tsara na shafin ya fi sirara, yana watsa haske ta hanyar sabili da haka yana da haske fiye da takardar da ke kewaye. Idan waɗannan layukan sun bambanta kuma suna daidai da juna, da/ko akwai alamar ruwa, to ana kiran takarda da takarda. Idan layukan sun bayyana azaman raga ko kuma ba a iya ganewa, da/ko babu alamar ruwa, to ana kiranta takarda saƙa. Wannan hanyar ita ake kira alamar ruwa ta zanen layi.
Silinda mold tsari
Wani nau'in alamar ruwa ana kiransa alamar ruwa ta Silinda mold. Alamar ruwa ce mai inuwa da aka fara amfani da ita a cikin 1848 wanda ya haɗa zurfin tonal kuma yana ƙirƙirar hoto mai launin toka. Maimakon yin amfani da abin rufe waya don nadi na dandy, alamar ruwa mai inuwa an ƙirƙira shi ta wuraren jin daɗi a saman nadi. Da zarar takarda ta bushe, ana iya sake birgima takardar don samar da alamar ruwa mai kauri ko da kauri amma tare da ɗimbin yawa. Alamar ruwa da aka samu gabaɗaya ta fi bayyane kuma mafi cikakkun bayanai fiye da waɗanda tsarin Dandy Roll ya yi, kuma don haka, Silinda Mold Watermark Paper shine mafi kyawun nau'in takarda mai alamar ruwa don takardun banki, fasfo, taken abin hawa, da sauran takaddun inda ya kasance muhimmin ma'aunin hana jabu.
 
## '''A kan tambarin aikawasiku'''
Duba kuma: Takarda tambarin aikawasiku
Alamar ruwa ta Crown CA da aka samo akan tambarin Commonwealth na Burtaniya da yawa (wanda aka gani daga baya)
Ambulan gidan waya na Amurka daga 1883 yana nuna alamar ruwa mai haske akan takarda da aka shimfiɗa
A cikin philately, alamar ruwa shine maɓalli mai mahimmanci na tambari, kuma sau da yawa yakan zama bambanci tsakanin tambari na gama-gari da wanda ba kasafai ba. Masu tarawa waɗanda suka ci karo da tambari iri ɗaya guda biyu tare da alamomin ruwa daban-daban suna ɗaukar kowane tambari a matsayin wani lamari daban da za a iya ganewa.Alamar ruwa ta “classic” ƙaramin kambi ne ko wata alama ta ƙasa, yana bayyana ko dai sau ɗaya akan kowane tambari ko tsari mai ci gaba. Alamun ruwa sun kusan gama duniya akan tambari a ƙarni na 19 da farkon karni na 20, amma gabaɗaya sun daina amfani da su, amma wasu ƙasashe suna ci gaba da amfani da su.
Wasu nau'ikan embossing, kamar waɗanda aka yi amfani da su don yin ƙirar "cross on oval" a kan tambarin farko na Switzerland, suna kama da alamar ruwa ta yadda takardar ta fi sirara, amma ana iya bambanta ta hanyar samun gefuna masu kaifi fiye da yadda aka saba don alamar ruwa ta al'ada. Alamomin ruwa na takarda tambarin kuma suna nuna ƙira iri-iri, haruffa, lambobi da abubuwan hoto.
## Manazarta