Results found: 2

Search results

Search:
in the keywords: chemical analyses

Sort By:

Limit search:

Badania obrazu Jana Lievensa „Portret młodzieńca”

100%

Frączek P., Klisińska-Kopacz A., Rogóż M., Wiłkojć E.

Opuscula Musealia

2011

vol. 19

49-54

In order to determine in detail the structure of the painting, physical and chemical analyses were carried out, such as: UV light examination, IR light examination, X-ray, chemical analysis of the ground layer and pigments (of the original paint layer as well as the overpaint layers). The stratigraphy of the existing layers was determined based on the examination of the cross-sections. Pigments were identified by the analysis of their elemental contents. Chemical analyses were carried out using noninvasive methods. Measurements were carried out using X-ray fluorescence spectroscopy (XRF).

Badania składu chemicznego szkieł odkrytych na osadzie kultury lateńskiej w Podłężu koło Krakowa

88%

Purowski T., Wagner B.

Przegląd Archeologiczny

2015

vol. 63

125-146

In Podłęże near Kraków, 63 pieces of glass were discovered on the settlement of the La Tène culture (Dzięgielewski and Purowski 2011). The chemical composition of 22 pieces of glass from 14 objects from this site (6 bracelets, 1 necklace spacer and 7 beads) have been discussed in this article (Fig. 1; Table 1). Items made undoubtedly in Celtic workshops have been selected, as well as those probably not connected with the Celtic culture, but dated to the La Tène period (cube-shaped bead – Fig. 1:57). A strongly damaged light blue bracelet (Fig. 1:105) and a fragment of necklace spacer (Fig. 1:103), discovered in the same building No. 1965, have been recognized as one of the oldest glass items from this site (LT C1 or perhaps even LT C1a). According to the initial hypothesis, the bracelet was thought to represent the 12a Group following the classification by Th. E. Haevernick (1960), corresponding to the Row 2-3 or 7 by R. Gebhard (1989). Somewhat younger fragment of a bracelet from the 13a Group (Row 4) (Fig. 1:102) was found in the feature No. 487, which can be dated to LT C1b-C2 (Dzięgielewski and Purowski 2011, Table 2:18). Two pieces of light purple bracelets (Fig. 1:101, 106) belong to the 6a Group or to the Row 11a. The colour of the glass from Podłęże is different from the late La Tène glassware, so it has been considered to be attributed most likely to the LT C1b (Dzięgielewski and Purowski 2011). The fragment of a bracelet or an armlet made of blue glass and decorated with white and yellow strands, referring to the 11b subgroup and the Row 19 (Fig. 1:104), has been dated to the LT C1b-C2. According to the formal classification, the youngest bracelet from the discussed set of glassware is an item probably representing the 7b Group (similar to the Row 14), made of amber-coloured and white glass (Fig. 1:107). Beads discovered in Podłęże (Fig. 1:52-58) represent the formal types, which cannot be accurately placed in a specific phase of the La Tène period (Dzięgielewski and Purowski 2011). Analyses of the chemical composition of the glasses from Podłęże were made using the LA-ICP-MS method (Laser Ablation Inductively Coupled Plasma Mass Spectroscopy) (Table 3). The parameters describing the operating conditions of the laser are provided with parameters describing the operation of the ICP-MS in Table 2. The glass object discovered in Podłęże (except the sample No. 105) were melted using sand and natural soda. They are the so-called LMG glass (Low Magnesium Glass) – characterized by low potassium and magnesium content (Fig. 2; 6), made according to the East Mediterranean traditions and spread in Europe since the Hallstatt Period. Together with sand, other additions – except silica –could also get to the glass objects from Podłęże, including aluminium, iron, magnesium, calcium, barium, strontium, and zirconium (Figs. 3-5; 7). It cannot be excluded that, in the case of some glass objects, a third component (except sand and natural soda), i.e. the calcium-magnesium alloy, was added to the glass. However, it is equally probable that the glass objects were made according to the two-component formula (in this case, calcium and magnesium would get to the glass together with other materials – mainly with sand). Cobalt certainly had the biggest influence on the blue colour of glass from Podłęże. For transparency and colour of other glass are responsible: in case of purple glass objects – manganese, black – iron and titanium, yellow – lead antimonate, white – calcium antimonate, yellowish – calcium antimonate and manganese compounds. Probably the iron compounds, which got to the glass together with sand, caused that the glass object No. 107b is amber-coloured. The chemical composition of the glass bracelet considered to be the oldest on the discussed site (the sample No. 105) significantly differs from the other glassware – it represent “potassium” glass (Fig. 2:1), which was not known to the Celts; most likely it was made much later. Amber-coloured glass (Fig. 1:107b) of the typologically youngest bracelet from Podłęże (probably from the 7b Group), dated to the turn of the LT C / D (Dzięgielewski and Purowski 2011), does not differ significantly from the other glass in terms of chemical composition (the only difference is that it does not contain a larger amount of colouring agents, such as cobalt and copper). A large amount of manganese has been discovered in light purple glass, which allows to formulate a hypothesis that this component was used for colouring light purple glass earlier (from the LT C1b) than it was thought so far (Dzięgielewski and Purowski 2011). Glass of the cube-shaped bead (dated to the La Tène period, but not related to the Celtic culture; Fig. 1:57), clearly differs from the other glass. To produce the bead, main materials of different chemical composition were used and colorants were added in different proportions than in the case of the Celtic glass (cf. Fig. 4; 6; 7). Most likely, glass of this bead was made in another workshop than the Celtic glass discovered in Podłęże. The glass from Podłęże is of similar chemical composition to other glass objects from Central Europe (cf. e.g. Venclová et al. 2009; Březinova et al. 2013). Comparing the glass objects described in this paper to the glass discovered on the settlement in Němčice in Moravia, they can be assigned to the A, B, C and F groups according to the classification by N. Venclová et al. (2009). And comparing to the glass from Austria, the glass objects from Podłęże have lower content of strontium and zirconium (Figs. 4 and 5). Because the main components of the Celtic glass from different areas of Europe from the third to the first century BC are usually at a similar level, it is probable that the glass was made from similar materials and according to the same formula. It is not certain whether glass used in the Celtic ornaments was melted in Europe or in East Mediterranean workshops (Březinova et al. 2013). These materials were produced using mineral soda (natron), unknown in Central Europe, which may indicate the latter area. It is possible therefore that glass from which the Celts made original jewellery was melted in glassworks working in the East Mediterranean area, and then in the form of semi-finished products was delivered to Celtic workshops. At the present stage of research it is difficult to say whether the glass went to Europe as a ready-made material that does not require the addition of colorants, or colour and transparency of glass were a result of works of local workshops in Europe (Venclová et al. 2009).

Refine search results

1 Opuscula Musealia

1 Przegląd Archeologiczny

1 Frączek P.

1 Klisińska-Kopacz A.

1 Purowski T.

1 Rogóż M.

1 Wagner B.

1 Wiłkojć E.

1 2015

1 2011

Search results

Badania obrazu Jana Lievensa „Portret młodzieńca”

Badania składu chemicznego szkieł odkrytych na osadzie kultury lateńskiej w Podłężu koło Krakowa